The present invention relates to circuit modules, and more particularly to a card type circuit module and a fabricating method thereof.
In the Digital Age, a card type circuit module such as a multi-media card (MMC) or a secure digital card (SD), which is a type of flash memory circuit module with high storage capacity, is developed. This type of circuit card module can be coupled to any data platform such as a personal computer (PC), a personal Digital Assistant (PDA), a digital camera and a multi-media browser, for storing and retrieving a variety of digital multi-media data.
The fabrication method of a prior-art circuit card module comprises the steps of: firstly, performing a chip mounting process to mount a chip on a substrate; secondly, electrically connecting the chip to electrical connection pads of the substrate by means of soldering via bonding wires; then performing an encapsulating process to form an encapsulant on the substrate for encapsulating the chip and the bonding wires disposed on the substrate; lastly, inserting the substrate and the encapsulant into a casing so as to form a card module. Similar techniques may be found in U.S. Pat. Nos. 5,677,524 and 6,040,622 and T.W. Patent No. 570,294.
Furthermore, referring to U.S. Pat. Nos. 5,677,524 and 6,040,622, both patents suggest having a plurality of chips directly stacked on the substrate. However, the thinnest substrate known to date is 210 μm thick and a typical chip is 75 μm thick. Therefore, as shown in
T.W. Patent No. 570,294, on the other hand, discloses another type of circuit card modules, using a substrate with a smaller size of 10 mm*18 mm as a chip carrier. Thus the substrate can be reduced to almost the same size as the area covered by the chip in order to lower the cost of production.
Nowadays, in order to satisfy consumer's ever-increasing demand for higher quality multimedia, a lot of new digital devices are developed to have better performances and more functions. For example, a new digital camera may boost its performance by improving its resolution of 1 million pixels to 5 million pixels or more. In response to that, the memory capacity of the circuit card module must be increased correspondingly. For instance, an earlier product can only hold a capacity of 32 MB, 64 Mb, or 128 Mb, but now it can hold a capacity of 1 GMb up to 4 GMb. In order to upgrade the memory capacity, the size of the chip has to be increased correspondingly. However, according to the teachings of T.W. Patent No. 570,294, the size of the substrate has to be correspondingly increased as well in order to accommodate the enlarged chip that has larger memory capacity. In other words, when the memory capacity and size of the chip increases, the substrate of T.W. Patent No. 570,294 must be increased in size, leading to an increase of substrate material cost. Accordingly, problems in having the limitation of chip stacking due to the thickness of the substrate and the high production cost are remained unsolved by the teachings of T.W. Patent No. 570,294.
Moreover, as the size and height of the circuit card module must be compatible with the specifications announced by Multi-Media Card Association (MMCA) and Secure Digital Association (SDA), it becomes a big challenge to upgrade the memory capacity within the limited space of the circuit card module.
Therefore, a need still remains for developing a circuit card module and the fabricating method thereof, which is capable of reducing the size of substrate, stacking multiple chips without being limited by the thickness of the substrate, preventing an increase in the size of the substrate due to variation of different chip size, as well as reducing the cost of production.
In light of the shortcoming of the above prior arts, a primary objective of the present invention is to provide a circuit card module and a fabricating method thereof, which can minimize the size/thickness of a substrate.
Another objective of the invention is to provide a circuit card module and a fabricating method thereof, which can stack a plurality of chips without being limited by the thickness of a substrate.
Still another objective of the invention is to provide a circuit card module and a fabricating method thereof, which is capable of reducing the size of a substrate and making it compatible with different sizes of chips.
In order to achieve the foregoing and other objectives, the present invention discloses a circuit card module and a fabricating method therefore. The circuit card module comprises: a substrate providing a surface having a surface sufficiently large to form an electrical connecting portion thereon for electrically connecting to external devices; at least a first chip mounted on and electrically connected to the substrate; and at least a second chip electrically connected to the substrate, wherein at least a surface of the second chip is co-planar with the substrate.
In the foregoing circuit card module, the first chip is electrically connected to the substrate via bonding wires. The first chip may be a controller die and the second chip may be a memory die. In one preferred embodiment, a plurality of second chips are stacked over each other in a step-like manner and electrically connected to the substrate. In another preferred embodiment, the second chips are electrically connected to each other via bonding wires, wherein at least one of the second chips is electrically connected to the substrate via bonding wires.
The circuit card module may further comprise an encapsulant and a casing. The encapsulant is employed for encapsulating the first chip, the second chips, and the substrate, whereas the casing is employed for covering the encapsulant but allowing the electrical connecting portion to be exposed therefrom.
The fabricating method of the circuit card module disclosed by the present invention, comprises: providing a carrier defined with at least a first and a second carrying regions; respectively mounting a substrate having a first chip electrically connected thereto on the first carrying region, and at least a second chip electrically connected to the substrate on the second carrying region, wherein the substrate has at least a surface sufficiently large enough to form an electrical connecting portion thereon for electrically connecting to external devices.
In the foregoing fabricating method, the carrier may be a board selected from a group consisting a glass board, a plastic board, and a metallic board, wherein a surface of the carrier may be formed with an adhesive. In one preferred embodiment, the carrier may be a glass board and the adhesive layer may be an UV layer, wherein adhesiveness of the adhesive layer can be removed by means of UV light in order to remove the carrier. In another preferred embodiment, the carrier may be a plastic board and the adhesive layer may be an acrylic adhesive layer, wherein the adhesive layer can be removed by means of mechanical backgrinding in order to remove the carrier. Yet, in another preferred embodiment, the carrier may be a metallic layer and the adhesive may be an acrylic adhesive layer, wherein adhesiveness of the adhesive layer can be removed by means of chemical agents in order to remove the carrier.
Furthermore, in another preferred embodiment, a plurality of second chips are employed in a semiconductor package, wherein the second chips are electrically connected to each other via bonding wires. There are different ways of stacking the second chips on the carrier. For example, the second chips may be sequentially stacked on top of each other on the second carrying region, or be staked in a step-like manner in advance and then mounted on the second carrying region. Moreover, the substrate may be mounted on the first carrying region and electrically connected to the first chip, before stacking the second chips on the second carrying region. Yet, as another alternative, the substrate may be mounted on the first carrying region and the second chips may be stacked and mounted on the second carrying region, before respectively electrically connecting the first chips and the second chips to the substrate.
Preferably, the foregoing fabricating method further comprises the steps of: forming an encapsulant for encapsulating the substrate, the first chip and the second chips; removing the carrier. Moreover, after removing the carrier, a singulation process is performed. In addition, the foregoing fabricating method may further comprise the steps of: providing a casing for covering the encapsulant but allowing the electrical connecting portion to be exposed therefrom, wherein the casing may be pre-fabricated, or formed by injection modeling during fabrication processes. The present invention allows a plurality of semiconductor packages to be fabricated in batch, so as to reduce production cost.
Comparing to prior arts, as the substrate of the present invention only requires a minimum surface to form an electrical connecting portion for electrically connecting to external devices, only a small amount of the substrate materials will be consumed for fabricating a circuit card module. In addition, as aforementioned, because the present invention is capable of stacking multiple chips without being limited by the thickness of the substrate, the present invention can produce a circuit card module comprising more chips than the prior arts do. For instance, the present invention can deliver a circuit card module containing more than two staked chips. And withal, because the substrate of the present invention only need to comprise an electrical connecting portion thereof, the present invention can minimize the substrate size regardless of the size of the chips and increase memory capacity without changing the appearance of the circuit card module. Last but not the least, the carrier described herein may be re-used again and again after being removed from the substrate so as to reduce the cost of production. Accordingly, the present invention is a very valuable industrial application, which outperforms the prior arts by the foregoing unique advantages.
Certain embodiments of the invention have other aspects in addition to or in place of those mentioned above. The aspects will become apparent to those skilled in the art from a reading of the following detailed description when taken with reference to the accompanying drawings.
The present invention can be more fully understood by reading the following detailed description of the preferred embodiments, with reference made to the accompanying drawings, wherein:
FIGS. 1 to 3 in conjunction with
In the following description, numerous specific details are given to provide a thorough understanding of the invention. However, it will be apparent that the invention may be practiced without these specific details. In order to avoid obscuring the present invention, some well-known configurations and process steps are not disclosed in detail.
Likewise, the drawings showing embodiments of the structure are semi-diagrammatic and not to scale and, particularly, some of the dimensions are for the clarity of presentation and are shown greatly exaggerated in the drawing. Similarly, although the views in the drawings for ease of description generally show similar orientations, this depiction in the drawings. is arbitrary for the most part. Generally, the invention can be operated in any orientation.
For expository purposes, the term “horizontal” as used herein is defined as a plane parallel to the plane or surface of the substrate, regardless of its orientation. The term “vertical” refers to a direction perpendicular to the horizontal as just defined. Terms, such as “on”, “above”, “below”, “bottom”, “top”, “side” (as in “sidewall”), “higher”, “lower”, “upper”, “over”, and “under”, are defined with respect to the horizontal plane.
The first embodiment of the circuit card module of the present invention and the method of fabricating the same is illustrated in FIGS. 1 to 4B and exemplified using a multi-media card (MMC). However, the present invention can also be applied to form other types of circuit cards, which have different functions and sizes, such as SD cards.
In this preferred embodiment, the fabricating method of the circuit card module comprises: providing a carrier having at least a first carrying region and a second carrying region, wherein the first carrying region is co-planar with the second carrying regions; and, respectively, mounting a substrate that is electrically connected to a first chip on the first carrying region, and a second chip that is electrically connected to the substrate on the second carrying region. Additionally, any substrate that is sufficiently large enough for the substrate to be electrically connected to an external device may be employed.
Referring to
It should be noted that the carrier 1 of this preferred embodiment comprises the first carrying region 11 and the second carrying region 13, however, it should not be limited thereto. For instance, any carrier that is predefined with a first carrying region and a second carrying region may be employed. Moreover, the carrier 1 described herein may be a gold board, a plastic board, or any other types of boards made of other appropriate materials.
Next, a substrate 3 and a second chip 6 are respectively mounted on the first carrying region 11 and the second carrying region 13, wherein a first chip 5 is mounted on and electrically connected to the substrate 3 in subsequent processes.
Referring to
Subsequently, as shown in
Then, referring to
Accordingly, a circuit card module at least comprises: a substrate 3 having a third electrical connecting portion 37 for electrically connecting to external devices, a first chip 5 disposed on the substrate 3, a second chip 6 electrically connected to the substrate 3, wherein the second chip 6 has a surface that is co-planar with the substrate 3. In this preferred embodiment, the first chip is a controller die and the second chip 6 is a memory die.
Yet, in order to increase memory capacity, the first carrying region ad second carrying region may respectively accommodate a substrate equipped with a first chip, and a plurality of second chips stacked on top of each other, wherein the first chip is electrically connected to the substrate.
Moreover, the a substrate and a plurality of second chips stacked on top of the other may be disposed on the first carrying region and the second carrying region respectively, and the first chip may be electrically connected to the substrate.
According to the foregoing, a third chip mounting process may be performed to increase memory capacity. As depicted in
The schematic views of a second embodiment of the circuit card module of the present invention and the fabrication method thereof are shown in
One of the major differences between the second embodiment and the first embodiment are that, in the first embodiment, only one or two chips are stacked on the carrier, and the size/thickness of the substrate are minimized; whereas, in the second embodiment, more than two second chips are stacked on the carrier without limiting the size/thickness of the substrate. In other words, the size/thickness of the substrate is highly adjustable, so as to allow the substrate to be compatible with the chips and the bonding wires formed thereon.
As shown in
Next, as shown in
Subsequently, as shown in
Lastly, referring to
Furthermore, as shown in
In addition, any substrate of any size may be employed as long as it is has an area sufficiently large enough to form the third electrical connecting portion 37 thereon for electrically connecting to external devices. In this embodiment, the first chip 5 is disposed on the chip mounting region 31 and electrically connected to the first electrical connecting portion 33 via the bonding wires 51, wherein the first chip 5 is a controller die. Moreover, the stacked second chips 6, 6′, 6″ and 6″′ are electrically connected with each other via the bonding wires 63, 65 and 67, wherein second chips 6, 6′ 6″ and 6″′ are memory dies and the bonding wires 51, 61, 63, 65 and 67 are gold wires. The casing 9 may be pre-made, or directly formed by means of injection modeling during the fabricating process.
The schematic views of a third embodiment of the circuit card module of the present invention and the fabrication method thereof are shown in
Comparing the third embodiment to the first embodiment, one of the major differences therebetween is that an arrayed carrier is used to exemplify the third embodiment. In addition, the present embodiment can be applied to, but not limited to the fabrication of SD cards.
As shown in
Accordingly, it should be understood by a person having ordinary skill in the art that the design, arrangement and configuration of the present invention is highly flexible. For example, the present invention may employ a miniaturized substrate or other substrates suitable for electrically connecting to chips. Moreover, the carrier for carrying the substrate, first chip, and second chip can be configured as a single unit or arranged in a row to form a multi-carrier array. In addition, in one embodiment, as the arrayed carriers may be fabricated in batch, the fabricating cost can thus be dramatically reduced.
Moreover, although four second chips 6, 6′, 6″ and 6″′ are used to exemplify the foregoing embodiments, circuit cards other than multi-media circuit cards may be employed in another embodiments. Furthermore, methods of stacking the chips and the number of the stacked chips can be adjusted or modified according to predetermined standards or industrial requirements. Therefore, alternatives of the foregoing embodiments should not be limited to what has been disclosed herein.
Besides, as the substrate 3 of the present invention does not have the second chips 6, 6′, 6″ and 6″′ attached thereto, the thickness of the substrate 3 will not affect the spaces available for stacking the second chips 6, 6′, 6″ and 6″′. In other words, a single layer circuit board or a multi-layered circuit board may be employed as the substrate.
Concluded from the above, the circuit card module of the present invention and the fabricating method thereof are capable of reducing 50% of materials used for the substrate by minimizing the size of the substrate, as compared to the prior art. In other words, the present invention can reduce the amount of fabrication materials used for the substrate to a minimum degree, thereby reducing the cost of production dramatically. Moreover, comparing to the prior art as shown in
Last but not the least, in a circuit card module of any standard, the present invention provides much more spaces for stacking chips than the prior arts do. For example, the present invention is capable of stacking at least two more 75 μm chips in thickness as compared to the prior arts. Accordingly, the semiconductor package of the present invention is capable of accommodating more chips as well as reducing the size/thickness of and the material amount consumed by the substrate, without being limited by the sizes and the amount of chips.
While the invention has been described in conjunction with exemplary preferred embodiments, it is to be understood that many alternative, modifications, and variations will be apparent to those skilled in the art in light of the foregoing description. Accordingly, it is intended to embrace all such alternatives, modifications, and variations that fall within the scope of the included claims. The scope of the claims, therefore, should be accorded the broadest interpretation so as to encompass all such modifications and similar arrangements. All matters hithertofore set forth herein or shown in the accompanying drawings are to be interpreted in an illustrative and non-limiting sense.
Number | Date | Country | Kind |
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095116338 | May 2006 | TW | national |