1. Field of the Invention
The present invention relates generally to semiconductor packages and fabrication methods thereof, and more particularly to a sensor-type semiconductor package and fabrication method thereof.
2. Description of Related Art
Conventionally, to obtain an image sensor package, a sensor chip is mounted to a chip carrier and electrically connected to the chip carrier through the bonding wires, then the top surface of the sensor chip is covered by a glass such that image light can be captured by the sensor chip. Thereafter, the obtained image sensor package can be integrated to an external device such as a printed circuit board (PCB) for further being incorporated in various kinds of electronic products such as digital cameras, digital videos, optical mouse, mobile phones and finger print sensors.
U.S. Pat. No. 6,060,340, No. 6,262,479, and No. 6,590,269 disclose a sensor-type semiconductor package, wherein, a dam lattice is formed on a chip carrier for defining a space and a sensor chip is attached and electrically connected to the chip carrier and received in the space defined by the dam lattice, and then a glass is adhered to the dam lattice for enclosing the space. However, as sufficient space needs to be left on the chip carrier for disposing of the dam lattice, this kind of sensor-type semiconductor package is difficult to be reduced further in size.
In view of the above drawback, U.S. Pat. No. 6,995,462 discloses a sensor-type semiconductor package without the dam lattice. As shown in
However, due to poor adhesion force and variation of the environmental temperature, cracking C is occurred between side edges of the glass 15 and the encapsulant 16, as shown in
Therefore, there is an urgent need providing a sensor-type semiconductor package and fabrication method thereof that can overcome the above-mentioned drawbacks.
According to the above drawbacks, an objective of the present invention is to provide a sensor-type semiconductor package and a fabrication method thereof so as to avoid cracking between the light-permeable body and the encapsulant due to poor adhesion and thus prevent external moisture or particles from entering the semiconductor package that adversely degrades the lifetime of the product.
Another objective of the present invention is to provide a sensor-type semiconductor package and fabrication method thereof, which is free from the size limitation resulted from preserving a sufficient area for mounting the dam lattice thereon.
A further objective of the present invention is to provide a sensor-type package and fabrication method thereof without the need of keeping a certain distance between the sensor area and the electrode pads of the sensor chip, thereby increasing the design flexibility while reducing the size of the sensor chip.
In order to attain the above and other objectives, the present invention discloses a fabrication method of a sensor-type semiconductor package, which comprises the steps of: attaching a sensor chip to a chip carrier; electrically connecting the sensor chip to the chip carrier via a plurality of bonding wires; mounting a light-permeable body to the sensor chip with an adhesive layer as a partition therebetween, wherein the planar size of the light-permeable body is larger than the predefined planar size of the sensor-type semiconductor package to be formed; forming an encapsulant on the chip carrier for encapsulating the sensor chip and the bonding wires with the upper surface of the light-permeable body being exposed from the encapsulant; and cutting the light-permeable body, the encapsulant and the chip carrier according to the predefined planar size of the sensor-type semiconductor package so as to make the cut light-permeable body and the sensor-type semiconductor package have the same planar size.
The active surface of the sensor chip of the present invention has a sensor area and a plurality of electrode pads. The sensor area of the sensor chip is covered and sealed by the light-permeable body, which is mounted to the sensor chip with the adhesive layer as a partition therebetween. According to one embodiment, the adhesive layer is disposed between the sensor area and the electrode pads of the sensor chip. Alternatively, the adhesive layer is heated to a melting state for being disposed on the electrode pads and covering all over the end portions of the bonding wires connected to the sensor chip. After the adhesive layer is solidified, the sensor area is covered and sealed by the light-permeable body.
The sensor-type semiconductor package of the present invention can be fabricated in batch-type process by providing a module having a plurality of chip carriers, respectively attaching a plurality of sensor chips to the chip carriers, mounting a light-permeable body to each sensor chip, encapsulating the chip carriers and performing a cutting process to separate the sensor-type packages. In addition, the light-permeable body can be made of such as glass. In batch-type process, a plurality of glasses can be mounted respectively to the sensor chips or a whole piece of glass can be mounted to the sensor chips. In addition, the encapsulant can be filled between the chip carrier and the light-permeable body for encapsulating the sensor chip and the bonding wires by dispensing, wherein the upper surface of the light-permeable body is exposed from the light-permeable body. Alternatively, a molding process can be performed for forming the encapsulant.
According to another embodiment, after the encapsulating process, the light-permeable body can be bevel cut first along the predefined cutting path so as to form bevel edges on the side surfaces of the light-permeable body. Subsequently, a second cutting process is performed at positions of bevel edges of the light-permeable body so as to obtain a desired sensor-type semiconductor package. Such a method not only avoids cracking of the light-permeable body, but also increases lifetime of cutting tools.
Through the above fabrication method, the present invention discloses a sensor-type semiconductor package, comprising: a chip carrier; a sensor chip attached to the chip carrier and electrically connected with the chip carrier via a plurality of bonding wires; a light-permeable body mounted to the sensor chip with an adhesive layer as a partition therebetween; and an encapsulant formed between the chip carrier and the light-permeable body for encapsulating the sensor chip and the bonding wires, wherein an upper surface of the light-permeable body is exposed from the encapsulant and a planar size of the cut light-permeable body is the same as a planar size of the formed sensor-type semiconductor package. The active surface of the sensor chip has a sensor area and a plurality of electrode pads. The sensor area of the sensor chip is covered and sealed by the light-permeable body, which is mounted to the sensor chip with the adhesive layer as a partition therebetween. The adhesive layer can be disposed between the sensor area and the electrode pads of the sensor chip. Alternatively, the adhesive layer can be heated to a melting state for being disposed on the electrode pads and for covering all over the end portions of the bonding wires connected to the sensor chip. After the adhesive layer is solidified, the sensor area is covered and sealed by the light-permeable body.
Further, bevel edges can be formed at the side surfaces of the light-permeable body so as to increase lifetime of cutting tools. A rough structure can be formed on a portion of the light-permeable body corresponding to the encapsulant for increasing the adhesion force between the light-permeable body and the encapsulant.
Therefore, the sensor-type semiconductor package and the fabrication method thereof in the present invention mainly include attaching a sensor chip to a chip carrier and electrically connecting the sensor chip to the chip carrier via a plurality of bonding wires, then mounting a light-permeable body to the sensor chip for proceeding with a subsequent encapsulating process and a cutting process. As the initial planar size of the light-permeable body is larger than the predefined planar size of the sensor-type semiconductor package to be formed, the encapsulant can be completely formed between the chip carrier and the light-permeable body, that is, the contacting area between the light-permeable body and the encapsulant is maximized. Thus, after cutting according to the predefined planar size, the light-permeable body and the encapsulant completely adhered with each other is provided. With the help of the rough structure formed on the light-permeable body at portions being contacted with the encapsulant, the bonding of the light-permeable body can further be reinforced so as to prevent external moisture or particles from entering the package and adversely affecting the lifetime of the products.
Furthermore, the adhesive layer can be disposed between the sensor area and the electrode pads of the sensor chip. Alternatively, the adhesive layer can be heated to a melting state for being disposed on the electrode pads, and for covering all over the end portions of the bonding wires connected to the sensor chip. And after the adhesive layer is solidified, the sensor area can be covered and sealed by the light-permeable body, thus a step for preserving a space between the sensor area and the electrode pads for bounding for mounting the light-permeable body is bypassed in the present application. Such a method can reduce sizes of the sensor chip and the sensor-type semiconductor package, increase chip production, decrease chip cost and increase design flexibility of the sensor chip.
FIG. 3B′ is a schematic diagram showing another embodiment of mounting the light-permeable body to the sensor chip according to the present invention;
FIG. 4B′ is a schematic diagram showing a molding process for encapsulating the sensor chip according to the present invention;
The following illustrative embodiments are provided to illustrate the disclosure of the present invention, these and other advantages and effects can be apparent to those skilled in the art after reading the disclosure of this specification. The present invention can also be performed or applied by other different embodiments. The details of the specification may be on the basis of different points and applications, and numerous modifications and variations can be made without departing from the spirit of the present invention.
As shown in
Each sensor chip 20 has an active surface 201 and a non-active surface 202 opposed to the active surface 201, and the active surface 201 has a sensor area 203 and a plurality of electrode pads 204 formed thereon. The sensor chip 20 is attached to the chip carrier 21 through its non-active surface 202, and the electrode pads 204 of the sensor chip 20 are connected to the chip carrier 21 via a plurality of bonding wires 22 for electrically coupling the sensor chip 20 and the chip carrier 21. Non-active surfaces 202 of the sensor chips 20 can be thinned first and then the selected good dies are attached to the chip carriers 21. The chip carriers 21 can be such as substrates and leadframes.
As shown in
As shown in
As shown in
Through the above fabrication method, the present invention also discloses a sensor-type semiconductor package 2 (as shown in
As shown in
Each sensor chip 30 has an active surface 301 and a non-active surface 302 opposed to the active surface 301, and the active surface 301 has a sensor area 303 and a plurality of electrode pads 304 formed thereon. The sensor chip 30 is attached to the chip carrier 31 through its non-active surface 302, and the electrode pads 304 of the sensor chip 30 are connected to the chip carrier 31 via a plurality of bonding wires 32 for electrically coupling the sensor chip 30 and the chip carrier 31.
As shown in
When mounting the light-permeable bodies 35 to the sensor chips 30, the light-permeable bodies 35 are heated and a heating source is provided below the chip carriers 31 so as to melt the adhesive layers 34, and after the melted adhesive layers 34 contact the plurality of bonding wires 32 and covers all over the end portions of the plurality of bonding wires 32, the heating source is removed away. As a result, the adhesive layers 34 are solidified and the light-permeable bodies 35 can be supported by the solidified adhesive layers 34.
The adhesive layers 34 may be made of a B-stage epoxy resin formed on the light-permeable bodies 35. After the light-permeable bodies 35 are heated, the adhesive layers 34 enter a half-melting state and have adhesiveness. Accordingly, the light-permeable bodies 35 can be mounted to the sensor chips 30 at positions corresponding to the electrode pads 304 through the adhesive layers 34 and meanwhile, the end portions of the plurality of bonding wires 32 connected to the sensor chips 30 are covered by the adhesive layers 34.
As shown in FIG. 3B′, a mechanical arm 38 having heating function can be used to clip and heat the light-permeable body 35 so as to melt the adhesive layer 34 on the surface of the light-permeable body 35. The melted adhesive layer 34 further covering all over the end portions of the plurality of bonding wires 32 connected to the sensor chip 30. Thereafter, the mechanical arm 38 and the heating source are removed away and the adhesive layer 34 is cooled and solidified.
As shown in
As shown in
Through the above fabrication method, the present invention also discloses the sensor-type semiconductor package 3 (as shown in
As shown in
Further referring to FIG. 4B′, instead of using a dispensing method, the module 41A is disposed in a mold cavity 470 of a mold 47 with the top surface of the light-permeable body 45A abutting against the top portion of the mold cavity 470. By injecting the encapsulating material into the mold cavity 470, an encapsulant 46 encapsulating the sensor chip 40 and the bonding wires 42 can be formed.
As shown in
As shown in
Therefore, the sensor-type semiconductor package and the fabrication method thereof of the present invention mainly includes attaching a sensor chip to a chip carrier and electrically connecting the sensor chip to the chip carrier via a plurality of bonding wires, mounting a light-permeable body having an adhesive layer formed thereunder to the sensor chip, proceeding with a subsequent encapsulating process and a cutting process. As the initial planar size of the light-permeable body is larger than the predefined planar size of the sensor-type semiconductor package to be formed, the encapsulant can be completely formed between the chip carrier and the light-permeable body, that is, contacting area between the light-permeable body and the encapsulant is maximized. Thus, after cutting according to the predefined planar size, the light-permeable body and the encapsulant are completely adhered with each other. With the help of the rough structure formed on the light-permeable body at positions corresponding to the encapsulant, the bonding of the light-permeable body can further be reinforced so as to prevent external moisture or particles from entering the package and adversely affecting lifetime of the products.
Furthermore, the adhesive layer can be disposed between the sensor area and the electrode pads of the sensor chip. Alternatively, the adhesive layer can be heated to a melting state for being disposed on the electrode pads, and for covering the end portions of the plurality of bonding wires connected to the sensor chip. And after the adhesive layer is solidified, the sensor area is covered and sealed by the light-permeable body. Such a method can reduce sizes of the sensor chip and the sensor-type semiconductor package, increase chip production, decrease chip cost and increase the design flexibility of the sensor chip.
The above descriptions of the detailed embodiments are only to illustrate the preferred implementation according to the present invention, and it is not to limit the scope of the present invention, Accordingly, all modifications and variations completed by those with ordinary skill in the art should fall within the scope of present invention defined by the appended claims.
Number | Date | Country | Kind |
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095140686 | Nov 2006 | TW | national |