1. Field of the Invention
The present invention relates generally to sensor-type semiconductor devices and manufacturing method thereof, and more particularly to WLCSP (Wafer-Level Chip Scale Package) sensor-type semiconductor devices and manufacturing method thereof.
2. Description of Related Art
Conventionally, an image sensor package is obtained by mounting a sensor chip to a chip carrier and electrically connecting the senor chip to the chip carrier through bonding wires and covering top surface of the sensor chip with a glass such that image light can be captured by the sensor chip. The image sensor packages can further be integrated with external devices such as printed circuit boards (PCBs) so as to be applied in various kinds of electronic products such as digital cameras, digital videos, optical mice, mobile phones and so on.
Meanwhile, with rapidly increasing of the volume of information transmission, as well as miniaturization of electronic products, integrated circuits are required to have large number of I/O ports, high heat dissipation efficiency and miniaturized size and packages of the integrated circuits are required to have high electrical performance and small size. Therefore, WLCSP (Wafer-Level Chip Scale Package) sensor-type semiconductor devices with a size only slightly bigger than sensor chips thereof have been developed and efficiently applied in small sized electronic products.
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However, as the semiconductor devices have a reverse-trapezoid shape structure, a sharp angle is formed in joints of the electrical contacts and the corresponding conductive circuits, which causes the connection between the electrical contacts and the conductive circuits to break easily in case of a concentrated stress. Further, the notch formed at the back side of the wafer may be formed at a position deviate from a predefined position because of the difficulty in precise alignment. As a result, circuit connections cannot be established between the subsequently formed electrical contacts and the corresponding conductive circuits and even the chips can be damaged.
Meanwhile, the exposed electrical contacts can easily be polluted and accordingly the product reliability is decreased. Especially, when the bumps are reflowed for electrically connecting the semiconductor device to an external device such as a printed circuit board, the exposed electrical contacts may lead to a short circuit problem. Further the sputtering process used to form the conductive circuits and the electrical contacts complicates the manufacturing process. Also, the sputtering process and the plasma etching process result in an increased manufacturing cost.
Therefore, how to provide a sensor-type semiconductor device and a manufacturing method thereof that can overcome the above drawbacks has become urgent.
According to the above drawbacks, an objective of the present invention is to provide a sensor-type semiconductor device and a manufacturing method thereof so as to avoid broken joints of circuits due to a sharp angle.
Another objective is to provide a sensor-type semiconductor device and a manufacturing method thereof, through which can prevent circuits from being exposed and protect the circuits from being polluted by external environment so as to ensure product reliability and keep reliable external electrical connection.
A further objective is to provide a sensor-type semiconductor device and a manufacturing method thereof, which can prevent the prior art alignment error during cutting the back side of the wafer and accordingly prevent such problems as poor electrical connection and chip damage.
Still another objective is to provide a sensor-type semiconductor device and a manufacturing method thereof, which avoids using the plasma etching process and too much sputtering process so as to simplify the manufacturing process and decrease the manufacturing cost.
To achieve the above and other objectives, the present invention discloses a manufacturing method of a sensor-type semiconductor device, which comprises the steps of: providing a wafer comprising a plurality of sensor chips, wherein the wafer and each sensor chip have an active surface and a non-active surface opposed to the active surface, a sensor area and a plurality of solder pads are disposed on the active surface of each sensor chip, and a plurality of concave grooves is formed between the solder pads of adjacent sensor chips; filling a filling material into the concave grooves and forming first conductive circuits on the filling material for electrically connecting the solder pads of adjacent sensor chips; disposing a light permeable body on the wafer for covering the sensor areas and thinning the non-active surface of the wafer to a position where the concave grooves are located so as to expose the filling material; disposing the wafer to a carrier board through its non-active surface, wherein the carrier board has a plurality of second conductive circuits formed thereon corresponding in position to the filling material; cutting the light permeable body and the wafer corresponding to the concave grooves to a position where the second conductive circuits are located, thereby forming a plurality of first openings; forming metallic layers on the second conductive circuits in the first openings, the metallic layers electrically connecting the first and second conductive circuits of adjacent sensor chips; cutting the metallic layers in the first openings so as to form second openings smaller in width than the first openings, thereby breaking the first conductive circuit connections and the second conductive circuit connections of adjacent sensor chips, and meanwhile keeping the first and second conductive circuits of each sensor chip still electrically connected through the metallic layers; filling a dielectric material into the second openings for covering the metallic layers, the first and second conductive circuits; and removing the carrier board and singulating the wafer so as to obtain a plurality of sensor-type semiconductor devices.
The carrier board is made of a metallic material and the second conductive circuits are formed thereon by electroplating. The metallic layers are formed on the second conductive circuits by electroplating through the carrier board of metallic material and the second conductive circuits.
According to another embodiment of the present invention, the manufacturing method of a sensor-type semiconductor device comprises the steps of: providing a wafer comprising a plurality of sensor chips, wherein the wafer and each sensor chip have an active surface and a non-active surface opposed to the active surface, a sensor area and a plurality of solder pads are disposed on the active surface of each sensor chip, and a plurality of concave grooves is formed between the solder pads of adjacent sensor chips; filling a filling material in the concave grooves and forming first conductive circuits on the filling material for electrically connecting the solder pads of adjacent sensor chips; disposing a light permeable body on the wafer for covering the sensor areas and thinning the non-active surface of the wafer to a position where the concave grooves are located so as to expose the filling material; cutting the light permeable body and the wafer between the sensor chips so as to separate the sensor chips from each other, wherein the first conductive circuits and the filling material are exposed from sides of the sensor chips; disposing the sensor chips to a carrier board having a plurality of second conductive circuits formed thereon, wherein there exists spacing between the sensor chips, the second conductive circuits are located between the sensor chips and exposed from the spacing; forming metallic layers on the second conductive circuits in the spacing, the metallic layers electrically connecting the first and second conductive circuits of adjacent sensor chips; cutting the metallic layer in the spacing so as to form openings smaller in width than the spacing, thereby breaking the first conductive circuit connections and the second conductive circuit connections of adjacent sensor chips, and meanwhile keeping the first and second conductive circuits of each sensor chip still electrically connected through the metallic layers; filling a dielectric material in the openings for covering the metallic layers, the first and second conductive circuits; and removing the carrier board and singulating the wafer so as to obtain a plurality of sensor-type semiconductor devices.
The present invention further discloses a sensor-type semiconductor device, which comprises: a sensor chip having an active surface and a non-active surface opposed to the active surface, a sensor area and a plurality of solder pads being disposed on the active surface of the sensor chip; first conductive circuits formed at periphery of the active surface of the sensor chip and electrically connected with the solder pads; second conductive circuits formed at periphery of the non-active surface of the senor chip; metallic layers formed on sides of the sensor chip for electrically connecting the first and second conductive circuits; and a light permeable body disposed on the active surface of the sensor chip and covering the sensor area.
The sensor-type semiconductor device further comprises a filling material disposed between the metallic layers and sides of the sensor chip; a dielectric material covering sides of the sensor chip and the light permeable body for covering the metallic layers and the first and second conductive circuits; and a solder mask layer covering the non-active surface of the sensor chip, which has openings for exposing part of the second conductive circuits such that conductive elements can be disposed to the exposed second conductive circuits for external electrical connection.
Therefore, according to the sensor-type semiconductor device and manufacturing method of the present invention, a wafer comprising a plurality of sensor chips is provided and a plurality of concave grooves is formed between solder pads on the active surface of adjacent sensor chips; a filling material is filled into the concave grooves and first conductive circuits are formed electrically connecting the solder pads of adjacent sensor chips; a light permeable body is disposed on the wafer and the non-active surface of the wafer is thinned to expose the filling material; the wafer is then disposed on a carrier board having a plurality of second conductive circuits formed corresponding in position to the filling material and the first conductive circuits; the light permeable body and the wafer are cut corresponding to the concave grooves to a position where the second conductive circuits are located, thereby forming first openings; metallic layers are formed in the first openings by electroplating and the metallic layers electrically connect the first and second conductive circuits of adjacent sensor chips; the metallic layers in the first openings are cut so as to form second openings smaller in width that the first openings, thus, the first conductive circuit connections and the second conductive circuit connections of adjacent sensor chips are broken, and meanwhile the first and second conductive circuits of each sensor chip can still be electrically connected through the metallic layers; a dielectric material is filled into the second openings so as to cover the metallic layers and the first and second conductive circuits; the carrier board is removed, and each of the sensor chips is separated from each other to form a plurality of sensor type semiconductor devices. Alternatively, the wafer can be thinned and singulated first, and then the obtained plurality of sensor chips is disposed on a carrier board with a plurality of second conductive circuits. Thereafter, such processes as forming metallic layers for electrically connecting the first and second conductive circuits, filling dielectrical material in the openings and breaking electrical connections between adjacent sensor chips are performed so as to obtain a plurality of sensor-type semiconductor devices. The invention prevents forming of slanting notches as in the prior art, prevents sharp angles from being formed at joints of electrical contacts and conductive circuits and further prevents displacement of the notches due to the difficulty in precise alignment, thus ensuring electrical connections between conductive circuits and protecting sensor chips from being damaged by concentrated stress. Further, as the dielectric material formed on sides of the sensor chip can protect the conductive circuits and the metallic layers from being polluted, the product reliability is ensured. Meanwhile, too much sputtering process and the plasma etching process are avoided to use in the present invention, thereby reducing the manufacturing cost and simplifying the manufacturing process.
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.
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The non-active surfaces of the sensor chips 20 are then thinned to a position where the concave grooves 205 are located so as to expose the filling material 22 in the concave grooves 205.
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The carrier board 25 can be a metallic board such as a copper board, on surface of which the second conductive circuits 26 are formed by electroplating. The second conductive circuits 26 can be Au/Ni, which is approximately 1 μm to 5 μm thick.
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Through the above described manufacturing method, a sensor-type semiconductor device is disclosed, which comprises: a sensor chip 20 having an active surface and a non-active surface opposed to the active surface, a sensor area 202 and a plurality of solder pads 201 being disposed on the active surface of the sensor chip 20; first conductive circuits 21 formed at periphery of the active surface of the sensor chip 20 and electrically connected with the solder pads 201; second conductive circuits 26 formed at periphery of the non-active surface of the sensor chip 20; metallic layers 27 formed on sides of the sensor chip 20 for electrically connecting the first and second conductive circuits 21, 26; and a light permeable body 23 disposed on the active surface of the sensor chip 20 and covering the sensor area 202 of the sensor chip 20.
The sensor-type semiconductor device further comprises a filling material 22 between the metallic layers 27 and sides of the sensor chip 20; a dielectric material 28 covering sides of the sensor chip 20 and the light permeable body 23 for covering the metallic layers 27 and the first and second conductive circuits 21, 26; and a solder mask layer 290 covering the non-active surface of the sensor chip 20, which has openings for exposing part of the second conductive circuits 26 such that conductive elements 29 can be disposed to the exposed second conductive circuits 26 for external electrical connection.
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A solder mask layer is formed on bottom of the sensor-type semiconductor device, and a plurality of openings are formed in the solder mask layer for exposing part of the second conductive circuits 36. Conductive elements such as bumps are disposed to the exposed second conductive circuits 36 such that the sensor-type semiconductor device can be electrically connected to an external device through the conductive elements.
Therefore, according to the sensor-type semiconductor device and manufacturing method of the present invention, a wafer comprising a plurality of sensor chips is provided and a plurality of concave grooves is formed between the solder pads on the active surface of adjacent sensor chips; a filling material is filled into the concave grooves and first conductive circuits are formed electrically connecting the solder pads of adjacent sensor chips; a light permeable body is disposed on the wafer and the non-active surface of the wafer is thinned to expose the filling material; the wafer is then disposed on a carrier board having a plurality of second conductive circuits formed corresponding in position to the filling material and the first conductive circuits; the light permeable body and the wafer are cut corresponding to the concave grooves to a position where the second conductive circuits are located, thereby forming first openings; metallic layers are formed in the first openings and electrically connect the first and second conductive circuits of adjacent sensor chips; the metallic layers in the first openings are cut so as to form second openings smaller in width than the first openings, thus, the first conductive circuit connections and the second conductive circuit connections of adjacent sensor chips are broken, and meanwhile the first and second conductive circuits of each sensor chip can still be electrically connected through the metallic layers; a dielectric material is filled into the second openings so as to cover the metallic layer and the first and second conductive circuits; the carrier board is removed, and each of the sensor chips is separated from each other to form a plurality of sensor type semiconductor devices. Alternatively, the wafer can be thinned and singulated first, and then the obtained plurality of sensor chips is disposed on a carrier board with a plurality of second conductive circuits. Thereafter, such processes as forming metallic layers for electrically connecting the first and second conductive circuits, filling dielectrical material in openings and breaking electrical connections between adjacent sensor chips are performed so as to obtain a plurality of sensor-type semiconductor devices. The invention prevents forming of slanting notches as in the prior art, prevents sharp angles from being formed at joints of electrical contacts and conductive circuits and further prevents displacement of the notches due to the difficulty in precise alignment concentrated stress, thus ensuring electrical connections between conductive circuits and protecting sensor chips from being damaged by concentrated stress. Further, as the dielectric material formed on sides of the sensor chip can protect the conductive circuits and the metallic layers from being polluted, the product reliability is ensured. Meanwhile, too much sputtering process and the plasma etching process are avoided to use in the present invention, thereby reducing the manufacturing cost and simplifying the manufacturing process.
The above-described 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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096111544 | Apr 2007 | TW | national |