Photosensitive module and method for forming the same

A method for forming a photosensitive module is provided. The method includes providing a sensing device. The sensing device includes a conducting pad located on a substrate. A first opening penetrates the substrate and exposes the conducting pad. A redistribution layer is in the first opening to electrically connect to the conducting pad. A cover plate is located on the substrate and covers the conducting pad. The method also includes removing the cover plate of the sensing device. The method further includes bonding the sensing device to a circuit board after the removal of the cover plate. The redistribution layer in the first opening is exposed and faces the circuit board. In addition, the method includes mounting an optical component corresponding to the sensing device on the circuit board. A photosensitive module formed by the method is also provided.

BACKGROUND OF THE INVENTION

Field of the Invention

The invention relates to a photosensitive module and methods for forming the same, and in particular to a photosensitive module with a sensing device formed by a wafer-level packaging process.

Description of the Related Art

A camera module is usually fabricated by chip on board (COB) technology. For example, a die is directly attached onto a printed circuit board (PCB) by adhesive glue. The die is electrically connected to the PCB by wire bonding processes. Next, a lens and a holder are mounted on the PCB.

However, it is necessary to press the die in order for it to be successfully attached to the PCB, using COB technology. As a result, it is difficult to reduce the thickness of the die. Otherwise, physical damage may be incurred. Furthermore, performing wire bonding processes to construct an electrically conductive path is necessary for the COB technology. The aforementioned fabrication process needs to be carried out in a clean environment, such as a clean room, to ensure the quality and yield of the camera module. Accordingly, the fabrication cost is high.

Thus, there exists a need to develop a novel photosensitive module and methods for forming the same, capable of mitigating or eliminating the aforementioned problems.

BRIEF SUMMARY OF THE INVENTION

An embodiment of the invention provides a method for forming a photosensitive module. The method comprises providing a sensing device. The sensing device comprises a conducting pad located on a substrate. The sensing device also comprises a first opening penetrating the substrate and exposing the conducting pad. The sensing device further comprises a redistribution layer formed in the first opening and electrically connected to the conducting pad. In addition, the sensing device comprises a cover plate located on the substrate and covering the conducting pad. The method also comprises removing the cover plate of the sensing device. The method further comprises bonding the sensing device to a circuit board after the removal of the cover plate. The redistribution layer in the first opening is exposed and faces the circuit board. In addition, the method comprises mounting an optical component corresponding to the sensing device on the circuit board.

An embodiment of the invention provides a photosensitive module. The photosensitive module comprises a sensing device bonded onto a circuit board. The sensing device comprises a conducting pad located on a substrate. The sensing device also comprises a first opening penetrating the substrate and exposing the conducting pad. The sensing device further comprises a redistribution layer located in the first opening and electrically connected to the conducting pad. The redistribution layer in the first opening is exposed and faces the circuit board. The photosensitive module also comprises an optical component corresponding to the sensing device and mounted on the circuit board.

DETAILED DESCRIPTION OF THE INVENTION

The making and using of the embodiments of the present disclosure are discussed in detail below. However, it should be noted that the embodiments provide many applicable inventive concepts that can be embodied in a variety of specific methods. The specific embodiments discussed are merely illustrative of specific methods to make and use the embodiments, and do not limit the scope of the disclosure. The disclosed contents of the present disclosure include all the embodiments derived from claims of the present disclosure by those skilled in the art. In addition, the present disclosure may repeat reference numbers and/or letters in the various embodiments. This repetition is for the purpose of simplicity and clarity, and does not imply any relationship between the different embodiments and/or configurations discussed. Furthermore, when a first layer is referred to as being on or overlying a second layer, the first layer may be in direct contact with the second layer, or spaced apart from the second layer by one or more material layers.

A chip package according to an embodiment of the present invention may be used to package micro-electro-mechanical system chips. However, embodiments of the invention are not limited thereto. For example, the chip package of the embodiments of the invention may be implemented to package active or passive devices or electronic components of integrated circuits, such as digital or analog circuits. For example, the chip package is related to optoelectronic devices, micro-electro-mechanical systems (MEMS), biometric devices, microfluidic systems, and physical sensors measuring changes to physical quantities such as heat, light, capacitance, pressure, and so on. In particular, a wafer-level package (WSP) process may optionally be used to package semiconductor chips, such as image-sensor elements, light-emitting diodes (LEDs), solar cells, RF circuits, accelerators, gyroscopes, fingerprint-recognition devices, microactuators, surface acoustic wave devices, pressure sensors, ink printer heads, and so on.

The aforementioned wafer-level packaging process mainly means that after the packaging step is accomplished during the wafer stage, the wafer with chips is cut to obtain individual packages. However, in a specific embodiment, separated semiconductor chips may be redistributed on a carrier wafer and then packaged, which may also be referred to as a wafer-level packaging process. In addition, the aforementioned wafer-level packaging process may also be adapted to form a chip package having multilayer integrated circuit devices by stacking a plurality of wafers having integrated circuits or to form a system-in-package (SIP).

Referring toFIG. 1E, a cross-sectional view of an exemplary embodiment of a photosensitive module300according to the invention is illustrated. The photosensitive module300comprises a circuit board260, a sensing device A and an optical component. In some embodiments, the sensing device A comprises a substrate100, conducting pads140, first openings190and a redistribution layer (RDL)220. The substrate100has a first surface100aand a second surface100bopposite thereto. In some embodiments, the substrate100may be a silicon substrate or another semiconductor substrate.

There is an insulating layer130on the first surface100aof the substrate100. In general, the insulating layer130may be made of an interlayer dielectric (ILD) layer, inter-metal dielectric (IMD) layers and a covering passivation layer. To simplify the diagram, only a single insulating layer130is depicted herein. In other words, the sensing device A comprises a chip/die, and the chip/die comprises the substrate100and the insulating layer130. In some embodiments, the insulating layer130may comprise an inorganic material, such as silicon oxide, silicon nitride, silicon oxynitride, metal oxide, another suitable insulating material or a combination thereof.

In some embodiments, one or more conducting pads140are in the insulating layer130on the first surface100aof the substrate100. In some embodiments, the conducting pads140may be a single conducting layer or comprise multiple conducting layers. To simplify the diagram, only two conducting pads140comprising a single conducting layer in the insulating layer130are depicted herein as an example. In some embodiments, the insulating layer130comprises one or more openings exposing the corresponding conducting pads140.

In some embodiments, the sensing device A further comprises a sensing or device region110and an optical element150. The sensing or device region110may be adjacent to the first surface100aof the substrate100, and may be electrically connected to the conducting pads140through interconnection structures (not shown). The sensing or device region110may comprise an image sensing element. For example, the sensing device may be a complementary metal oxide semiconductor (CMOS) image sensing device or another suitable image sensing device.

Furthermore, the optical element150is disposed on the first surface100aof the substrate100and corresponds to the sensing or device region110. In some embodiments, the optical element150may be a micro-lens array or another suitable optical element used for an image sensing device.

A spacer layer (or dam)160is disposed on the first surface100aof the substrate100, and covers the conducting pads140. Moreover, the spacer layer160has a cavity180surrounding the optical element150so that the optical element150is in the cavity180. In some embodiments, the spacer layer160does not substantially absorb moisture. In some embodiments, the spacer layer160may itself be adhesive and may contact none of the adhesion glue, thereby assuring that the spacer layer160will not move due to the disposition of the adhesion glue. Furthermore, since adhesion glue is not needed, the sensing device can be prevented from being contaminated by an overflow of the adhesion glue. In some other embodiments, the spacer layer160may be non-adhesive, and there may be an adhesive layer between the spacer layer160and the insulating layer130.

In some embodiments, the spacer layer160may comprise epoxy resin, inorganic materials (such as silicon oxide, silicon nitride, silicon oxynitride, metal oxide or a combination thereof), organic polymer materials (such as polyimide, butylcyclobutene (BCB), parylene, polynaphthalenes, fluorocarbons or acrylates), a photoresist material or another suitable insulating material.

The first openings190penetrate the substrate100and extend into the insulating layer130, thereby exposing the corresponding conducting pads140from the second surface100bof the substrate100. In some embodiments, the sensing device A further comprises a second opening200, which extends along the sidewall of the substrate100and penetrates the substrate100.

An insulating layer210is disposed on the second surface100bof the substrate100. The insulating layer210conformally extends to the sidewalls and the bottoms of the first opening190and the second opening200, and exposes the conducting pads140. In some embodiments, the insulating layer210may comprise epoxy resin, inorganic materials (such as silicon oxide, silicon nitride, silicon oxynitride, metal oxide or a combination thereof), organic polymer materials (such as polyimide, butylcyclobutene, parylene, polynaphthalenes, fluorocarbons or acrylates) or another suitable insulating material.

The patterned redistribution layer220is disposed on the second surface100bof the substrate100. The redistribution layer220conformally extends to the sidewalls and the bottom of the first opening190without extending into the second opening200. The redistribution layer220may be electrically isolated from the substrate100by the insulating layer210. The redistribution layer220may be in direct electrical contact with or indirectly electrically connected to the exposed conducting pads140through the first openings190. As a result, the redistribution layer220in the first openings190is also referred to as a through silicon via (TSV). In some embodiments, the redistribution layer220may comprise aluminum, copper, gold, platinum, nickel, tin, a combination thereof, a conductive polymer material, a conductive ceramic material (such as indium tin oxide or indium zinc oxide), or another suitable conductive material.

In some embodiments, the sensing device A is bonded to the circuit board260, and is electrically connected to the circuit board260through multiple conducting structures250. In some embodiments, the conducting structures250may be solder bumps, bonding pads, conductive glue or another suitable conductive structure. In some embodiments, the conducting structures250may comprise tin, lead, copper, gold, nickel, or a combination thereof. In some embodiments, the redistribution layer220in the first openings190is exposed and faces the circuit board260. In some embodiments, there is only an air gap sandwiched between a portion of the redistribution layer220and the circuit board260. In other words, there is no layer (such as an insulating material layer) between the redistribution layer220and the circuit board260.

Furthermore, an optical component of the photosensitive module300corresponds to the sensing device A and is mounted on the circuit board260. As a result, the spacer layer160is located between the optical component and the first surface100aof the substrate100. In some embodiments, the optical component comprises a holder270, a filter280and a lens290. The holder270comprises containing space or room, so that the filter280and the lens290are disposed within the space of the holder270and are fixed to the holder270. Therefore, the photosensitive module300is a fixed-focus device.

The capacity of the holder270is such that there is enough space to further accommodate the sensing device A on the circuit board260. As a result, the redistribution layer220of the sensing device A is in direct contact with the space of the holder270. In some embodiments, the filter280in the space is located between the lens290and the sensing device A so as to filter out infrared irradiation in light, which irradiates through the lens290towards the sensing device A. In some embodiments, the filter280is made of a light-transmissive material (such as glass) and a filter layer thereon. Furthermore, the lens290can be formed of a single lens set or comprise multiple lens sets. To simplify the diagram, only a flat filter280and a flat lens290are depicted herein. The structure of the optical component is determined by design requirements and is not limited thereto.

Referring toFIGS. 2, 3B, and 4, cross-sectional views of other exemplary embodiments of photosensitive modules400,500and600according to the invention are illustrated. Elements inFIGS. 2, 3B, and 4that are the same as those inFIG. 1Eare labeled with the same reference numbers as inFIGS. 2, 3B, and 4and are not described again for brevity.

The structure of the photosensitive module400shown inFIG. 2is similar to that of the photosensitive module300shown inFIG. 1E. The sensing device A in the photosensitive module300comprises the spacer layer160corresponding to the conducting pads140and disposed on the first surface100aof the substrate100. In contrast, a sensing device B in the photosensitive module400does not comprise a spacer layer, and the conducting pads140are exposed. As a result, the conducting pads140of the sensing device B are exposed and directly face the optical component.

Moreover, the differences between the photosensitive modules400and500also comprise that the first openings190and the second opening200of the sensing device B in the photosensitive module400are in communication with each other. As a result, the substrate100has a sidewall portion that is lower than the second surface100b. In other words, the thickness of the sidewall portion is less than the thickness of the substrate100. Moreover, an end220aof the redistribution layer220in the photosensitive module400extends to the sidewall of the first opening190, rather than extending on the second surface100bof the substrate100. In some embodiments, the sidewalls of the first opening190and the second opening200are inclined to the first surface100aof the substrate100.

The structure of the photosensitive module500shown inFIG. 3Bis similar to that of the photosensitive module300shown inFIG. 1E. One of the difference between them is that the photosensitive module300comprises the spacer layer160covering the conducting pads140while the photosensitive module500does not comprise a spacer layer, thereby exposing the conducting pads140. Furthermore, the differences also comprise that the photosensitive module300is a fixed-focus device while the photosensitive module500is a zoom (variable focus) device.

For example, the optical component in the photosensitive module500comprises underlying bracket510and filter280and overlying actuator520and lens290. The bracket510comprises containing space or room, such that the filter280is disposed within the space of the bracket510and is fixed to the bracket510. The capacity of the bracket510is such that there is enough space to further accommodate the sensing device A on the circuit board260. As a result, the filter280is located between the lens290and the sensing device A so as to filter out infrared irradiation.

In some embodiments, the actuator520may comprise a voice coil motor, an ultrasonic motor, a stepping motor, or another suitable actuator. The lens290is actuated to move in a direction that is away from or toward the sensing device A, so that the photosensitive module500has automatic zoom functions. To simplify the diagram, only a flat filter280, a flat lens290and a flat actuator520are depicted herein. The structure of the optical component is determined by design requirements and is not limited thereto.

It should be noted that the embodiment ofFIG. 3Bcan be implemented to the embodiments ofFIGS. 1E and 2, like the photosensitive module600shown inFIG. 4. The structure of the photosensitive module600is similar to that of the photosensitive module300. One of the differences between them is that the first openings190and the second opening200of the sensing device B in the photosensitive module600are in communication with each other. As a result, the end220aof the redistribution layer220in the photosensitive module400extends to the sidewall of the first opening190, rather than extending on the second surface100bof the substrate100. Furthermore, the differences also comprise that the photosensitive module300is a fixed-focus device while the photosensitive module600is a zoom device.

Embodiments of the invention replace a conventional die by a chip package to serve as a sensing device in a photosensitive module. In the aforementioned embodiments, the photosensitive modules300,400,500, and600comprise a front-side illumination (FSI) sensing device. However, in other embodiments, the photosensitive modules300,400,500, and600may comprise a back-side illumination (BSI) sensing device.

An exemplary embodiment of a method for forming a photosensitive module according to the invention is illustrated inFIGS. 1A to 1E, in whichFIGS. 1A to 1Eare cross-sectional views of an exemplary embodiment of a method for forming a photosensitive module300according to the invention.

Referring toFIG. 1A, a substrate100is provided. The substrate100has a first surface100aand a second surface100bopposite thereto, and comprises multiple chip regions120. To simplify the diagram, only a complete chip region and a partial chip region adjacent thereto are depicted herein. In some embodiments, the substrate100may be a silicon substrate or another semiconductor substrate. In some other embodiments, the substrate100may be a silicon wafer so as to facilitate the wafer-level packaging process.

There is an insulating layer130on the first surface100aof the substrate100. In general, the insulating layer130may be made of an ILD layer, IMD layers and a covering passivation layer. To simplify the diagram, only a single insulating layer130is depicted herein. In some embodiments, the insulating layer130may comprise an inorganic material, such as silicon oxide, silicon nitride, silicon oxynitride, metal oxide, a combination thereof, or another suitable insulating material.

In some embodiments, one or more conducting pads140are located in the insulating layer130in each of the chip regions120. In some embodiments, the conducting pads140may be a single conducting layer or comprise multiple conducting layers. To simplify the diagram, only two conducting pads140comprising a single conducting layer in the insulating layer130are depicted herein as an example. In some embodiments, the insulating layer130in each of the chip regions120comprises one or more openings exposing the corresponding conducting pads140so as to perform a pre-test through the exposed conducting pads140.

In some embodiments, a sensing or device region110is located in each of the chip regions120. The sensing or device region110may be adjacent to the first surface100aof the substrate100, and may be electrically connected to the conducting pads140through interconnection structures (not shown). Moreover, the sensing or device region110may comprise an image sensing element.

In some embodiments, the aforementioned structure may be fabricated by sequentially performing a front-end process and a back-end process of a semiconductor device. For example, the sensing or device region110and integrated circuits may be formed in the substrate100during the front-end process. The insulating layer130, the interconnection structures, and the conducting pads140may be formed on the substrate100during the back-end process. In other words, the following method for forming a chip package or a sensing device proceeds subsequently packaging processes to the substrate after the back-end process is finished.

In some embodiments, each of the chip regions120comprises an optical element150disposed on the first surface100aof the substrate100and corresponding to the sensing or device region110. In some embodiments, the optical element150may be a micro-lens array or another suitable optical element used for an image sensing device.

Afterwards, a spacer layer160may be formed on the insulating layer130by a deposition process (such as a coating process, a physical vapor deposition process, a chemical vapor deposition process or another suitable process). The spacer layer160covers the conducting pads140, and exposes the sensing or device region110and the optical element150. In some embodiments, the spacer layer160does not substantially absorb moisture. In some embodiments, the spacer layer160may be adhesive and may contact none of the adhesive glue, thereby assuring that the spacer layer160will not move due to the disposition of the adhesive glue. Furthermore, since the adhesive glue is not needed, the sensing device can be prevented from being contaminated by the overflow of the adhesive glue.

In some embodiments, the spacer layer160may comprise epoxy resin, inorganic materials (such as silicon oxide, silicon nitride, silicon oxynitride, metal oxide or a combination thereof), organic polymer materials (such as polyimide, butylcyclobutene, parylene, polynaphthalenes, fluorocarbons or acrylates) or another suitable insulating material. In some other embodiments, the spacer layer160may comprise a photoresist material, and may be patterned by exposure and developing processes to expose the sensing or device region110and the optical element150.

Next, the substrate100is bonded to a cover plate170through the spacer layer160. The spacer layer160forms a cavity180between the substrate100and the cover plate170in each of the chip regions120. As a result, the optical element150is located in the cavity180, and the optical element150in the cavity180is protected by the cover plate170. In some embodiments, the cover plate170may comprise glass or another suitable substrate material.

In some other embodiments, the spacer layer160may have been formed previously on the cover plate170. The substrate100is then bonded to the cover plate170through the spacer layer160on the cover plate170. In some embodiments, the spacer layer160may be formed on each of the substrate100and the cover plate170, and the substrate100may be bonded to the cover plate170through the two spacer layers160. In other embodiments, the spacer layer160may be non-adhesive, and there may be an adhesive layer between the spacer layer160and the substrate100and/or between the spacer layer160and the cover plate170.

In addition, in some other embodiments, the cover plate170is bonded to the substrate100by a temporary adhesive layer (such as a removable tape), rather than the spacer layer160. In this case, the temporary adhesive layer formed between the cover plate170and the substrate100substantially completely covers the first surface100aof the substrate100. For example, the temporary adhesive layer covers the conducting pads140, the sensing or device region110, and the optical element150.

Referring toFIG. 1B, a thinning process (such as an etching process, a milling process, a grinding process or a polishing process) using the cover plate170as a carrier substrate is performed on the second surface100bof the substrate100. As a result, the thickness of the substrate100is reduced. For example, the thickness of the substrate100may be less than about 100 μm.

Afterwards, multiple first openings190and a second opening200may be simultaneously formed in the substrate100in each of the chip regions120by a lithography process and an etching process (such as a dry etching process, a wet etching process, a plasma etching process, a reactive ion etching process, or another suitable process). The first openings190and the second opening200expose the insulating layer130from the second surface100bof the substrate100. In other embodiments, the first openings190and the second opening200may be respectively formed by a notching process, and lithography and etching processes.

In some embodiments, the first openings190correspond to the conducting pads140and penetrate the substrate100. Moreover, the second opening200extends along scribed lines SC between the adjacent chip regions120and penetrates the substrate100. As a result, portions of the substrate100in the chip regions120are separated from each other.

Referring toFIG. 1C, an insulating layer210may be formed on the second surface100bof the substrate100by a deposition process (such as a coating process, a physical vapor deposition process, a chemical vapor deposition process or another suitable process). The insulating layer210fills the first openings190and the second opening200, and is conformally deposited on the sidewalls and the bottoms of the first openings190and the second opening200. In some embodiments, the insulating layer210may comprise epoxy resin, inorganic materials (such as silicon oxide, silicon nitride, silicon oxynitride, metal oxide or a combination thereof), organic polymer materials (such as polyimide, butylcyclobutene, parylene, polynaphthalenes, fluorocarbons or acrylates) or another suitable insulating material.

Afterwards, portions of the insulating layer210on the bottom of the first openings190and the underlying insulating layer130are removed by lithography and etching processes. As a result, the first openings190further extend into the insulating layer130and expose the corresponding conducting pads140.

A patterned redistribution layer220is formed on the insulating layer210by a deposition process (such as a coating process, a physical vapor deposition process, a chemical vapor deposition process, an electroplating process, an electroless plating process or another suitable process) and lithography and etching processes. The redistribution layer220conformally extends to the sidewalls and the bottoms of the first openings190without extending into the second opening200.

The redistribution layer220is electrically isolated from the substrate100by the insulating layer210. The redistribution layer220may be in direct electrical contact with or indirectly electrically connected to the exposed conducting pads140through the first openings190. As a result, the redistribution layer220in the first openings190is also referred to as a TSV. In some embodiments, the redistribution layer220may comprise aluminum, copper, gold, platinum, nickel, tin, a combination thereof, a conductive polymer material, a conductive ceramic material (such as indium tin oxide or indium zinc oxide), or another suitable conductive material.

Afterwards, the insulating layers130and210, the spacer layer160and the cover plate170are diced along the scribed lines SC (equivalent to along the second opening200). As a result, multiple separated chip packages (i.e., sensing devices A) are formed.

In some embodiments, the first openings190and the second opening200are not completely filled or covered by the insulating layer210and the redistribution layer220. As a result, the redistribution layer220of the sensing device A is exposed. In some embodiments, the first openings190and the second opening200of the sensing devices A are spaced apart and completely isolated from each other through a portion of the substrate100(such as a sidewall portion). The subsequently formed redistribution layer220extends on the second surface100bbetween the first openings190and the second opening200. In other embodiments, the first openings190and the second opening200may be in communication with each other, like those of the sensing device B as shown inFIGS. 2 and 4. As a result, the end220aof the redistribution layer220extends to the sidewall of the first opening190, rather than extending on the second surface100bof the substrate100.

Referring toFIG. 1D, the cover plate170of the sensing device A is removed from the substrate100. As a result, the optical element150is exposed. In some embodiments, the spacer layer160remains on the insulating layer130. In some other embodiments, the spacer layer160may comprise a removable material. Therefore, the partial or entire spacer layer160may be removed as well. As a result, the conducting pads140are optionally exposed.

In addition, in some other embodiments, the cover plate170is bonded to the substrate100by a temporary adhesive layer (such as a removable tape). In this case, the temporary adhesive layer and the cover plate170of the sensing device A may be removed from the substrate100together. As a result, all the conducting pads140, the sensing or device region110, and the optical element150are exposed simultaneously, as shown inFIGS. 2 and 3A.

Afterwards, the sensing device A without the cover plate170is bonded onto a circuit board260. The sensing device A is electrically connected to the circuit board260through multiple conducting structures250between the redistribution layer220and the circuit board260.

In some embodiments, the conducting structures250may be formed by dipping flow technology. For example, the conducting structures250made of solder may have been formed previously on the circuit board260. A reflow process is then performed to bond the sensing device A and the circuit board260through solder bumps or bonding pads. Furthermore, before bonding the sensing device A onto the circuit board260, the required passive elements (such as inductors, capacitors, resistors or other electronic elements) may be formed on the circuit board260by surface mount technology (SMT). In addition, the sensing device A and the aforementioned passive elements may be simultaneously bonded onto the circuit board260by the same reflow process.

In other embodiments, the conducting structures250may be conductive glue or another conductive adhesive material so as to attach the sensing device A onto the circuit board260and form electrical connection paths through the conducting structures250. Furthermore, the required passive elements can have been formed previously on the circuit board260by surface mount technology before bonding the sensing device A onto the circuit board260. As a result, the sensing device (especially the sensing or device region110and the optical element150) can be prevented from being contaminated during the reflow process, thereby improving the quality of the photosensitive module.

Referring toFIG. 1E, an optical component is provided on the circuit board260. The optical component comprises a holder270, a filter280and a lens290. The holder270comprises containing space, so that the filter280and the lens290are disposed within the space of the holder270and are fixed to the holder270. Next, the optical component corresponds to the sensing device A and is mounted onto the circuit board260. As a result, the sensing device A on the circuit board260is also accommodated in the space of the holder270. The filter280is located between the lens290and the first surface100aof the substrate100. Therefore, the photosensitive module300is fabricated.

Since the first openings190and the second opening200are not completely filled or covered, the first openings190and/or the second opening200are in communication with the space of the holder270. In some embodiments, the circuit board260may be a panelized PCB or a de-panel board. When the circuit board260is a panelized PCB, the circuit board260can optionally be cut into de-panel boards after the optical component is mounted on the circuit board260.

In some embodiments, the filter280needs to be spaced apart from the sensing or device region110by an appropriate distance, so the photosensitive module can provide good image quality. In some embodiments, the filter280is formed of a light-transmissive material (such as glass) and a filter layer thereon. Furthermore, the lens290can be formed of a single lens set or comprise multiple lens sets. To simplify the diagram, only a flat filter280and a flat lens290are depicted herein. The structure of the optical component is determined by design requirements and is not limited thereto.

Another exemplary embodiment of a method for forming a photosensitive module according to the invention is illustrated inFIGS. 3A to 3B, in whichFIGS. 3A to 3Bare cross-sectional views of another exemplary embodiment of a method for forming a photosensitive module500according to the invention. Elements inFIGS. 3A to 3Bthat are the same as those inFIGS. 1A to 1Eare labeled with the same reference numbers as inFIGS. 1A to 1Eand are not described again for brevity.

Referring toFIG. 3A, a sensing device A may be formed by steps that are the same as or similar to the steps shown inFIGS. 1A to 1C. Subsequently, the cover plate170and the spacer layer160of the sensing device A may be removed from the substrate100by steps that are the same as or similar to the steps shown inFIG. 1D. As a result, the optical element150and the conducting pads140are exposed. Afterwards, the sensing device A may be bonded onto a circuit board260through conducting structures250.

Next, a bracket510having containing space is provided. A filter280is disposed within the space of the bracket510and is fixed to the bracket510. The bracket510is mounted on the circuit board260. As a result, the sensing device A on the circuit board260is also accommodated in the space of the bracket510, and the filter280corresponds to the sensing or device region110and the optical element150.

Subsequently, an actuator520and a lens290disposed therein are provided. In some embodiments, the actuator520may comprise a voice coil motor, an ultrasonic motor, a stepping motor, or another suitable actuator so as to provide automatic zoom functions. Afterwards, the actuator520and the lens290are mounted on the bracket510on the circuit board260. The lens290corresponds to the sensing or device region110and the optical element150. As a result, the filter280is located between the lens290and the sensing device A. Therefore, the photosensitive module500is fabricated.

In some embodiments, after mounting the bracket510and the filter280on the circuit board260and before mounting the actuator520and the lens290on the bracket510, an initial test may have been performed previously so as to test the image quality sensed by the sensing device A. The actuator520and the lens290are subsequently mounted. Accordingly, it helps ensure the reliability of the photosensitive module, and reduce the fabrication cost.

It should be noted that although the embodiments ofFIGS. 1A to 1E, andFIGS. 3A to 3Bprovide a method for forming a photosensitive module with a FSI sensing device, the method for forming external electrical connection paths (such as the opening in the substrate, the redistribution layer, the protection layer, or the conducting structures therein) can be implemented to the processes of a BSI sensing device.

In general, it is necessary to press a die in order to successfully attach it onto a PCB, using COB technology. Accordingly, the die should have a certain thickness (such as about 250 μm), in order to avoid causing physical damage during attachment.

According to the aforementioned embodiments, the sensing device is placed softly on the circuit board260during the process (such as a reflow process) for bonding the sensing device on the circuit board260. Therefore, the thickness of the substrate in the sensing device can be further reduced without occurring crack or damage problems in the substrate, thereby facilitating the shrinkage of the overall size of the photosensitive module.

Furthermore, a sensing device usually uses solder balls as external conducting structures and is bonded onto a circuit board through the solder balls. However, a sufficient amount of tin is required to ensure good bonding results. Therefore, it is difficult to reduce the height of the conducting structures.

According to some embodiments of the invention, the conducting structures250can have been formed previously on the circuit board260. The sensing device A is then bonded to the circuit board260through the conducting structures250(such as solder bumps). As a result, the height of the conducting structures250can be reduced, thereby facilitating the shrinkage of the overall size of the photosensitive module.

Furthermore, when the redistribution layer220of the sensing device is exposed, the sensing device can be successfully electrically connected to the conducting structures250on the circuit board260more easily. In addition, the conducting structures250may be conductive glue or another conductive adhesive material. Therefore, the height of the conducting structures250can be reduced even further. There is no need to perform a reflow process, thereby preventing the sensing device from being contaminated.

Moreover, the cover plate170is used to provide support and protection during the fabrication of the sensing device. Removing the cover plate170before bonding the sensing device to the circuit board260can facilitate reducing the overall height of the sensing device significantly, and increasing the light transmittance of the photosensitive modules. Furthermore, the cover plate170is only used as a temporary substrate and does not affect the sensing capability of the photosensitive module. Therefore, there is no need to use high-quality glass material as the cover plate170and an opaque substrate material may optionally be used.

In some embodiments, the sensing device is electrically connected to the circuit board260through the TSVs (i.e., the redistribution layer220in the first openings190) without performing bonding wire processes to form wires. Accordingly, the fabrication cost is significantly lowered. In addition, wafer-level chip scale packaging (CSP) technology is used in the invention to form sensing devices of photosensitive modules. Massive sensing devices can be fabricated, thereby further reducing the cost and the fabrication time.