Chip module and method for forming the same, electronic device

Abstract

The application discloses a chip module and a forming method thereof and an electronic device. The forming method of the chip module comprises the following steps: providing an optical sensing chip, the optical sensing chip having opposite first and second surfaces, a pad and a sensing area being formed in the first surface; etching the second surface of the optical sensing chip to form a plurality of light vias corresponding to the sensing area in the optical sensing chip, the light vias being used for conducting light signals to the sensing area; filling a light-transmitting layer in the light vias; forming a conductive structure on the same side of the second surface, the conductive structure being connected to the pad; and forming an optical structure above the light-transmitting layer. The method can help reduce the thickness of the chip module.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of sensing, in particular to a chip module and a forming method thereof, and an electronic device. BACKGROUND

[0002] Recently, the development trend of electronic products such as mobile phones is close to full-screen and thinning, and the thinning of the total thickness of the full-screen mounted under-screen biological detection and recognition module has become an urgent demand. Currently, the traditional COB (chip on board) scheme is usually used in the industry, but the traditional COB (chip on board) scheme requires the use of a holder to match the optical lens for the terminal, resulting in a relatively large overall thickness, which cannot meet the existing technical requirements.

[0003] With the continuous development and progress of technology, the emergence of microlenses has directly replaced traditional camera lenses, directly reducing the thickness of the lens in the module from millimeters to microns, further reducing the module thickness. However, the structure of the microlens relies on optical elements such as glass, and the separate optical microlens part needs to be individually attached to the chip. The alignment accuracy requirement in this step is relatively strict, resulting in relatively low production capacity and yield. And the microlens relies on optical elements, making the chip module thickness larger.

[0004] How to further reduce the thickness of the chip module is a problem to be solved at present. SUMMARY

[0005] In view of this, the present application provides a chip module and a forming method thereof, and an electronic device to reduce the thickness of the chip module.

[0006] The forming method of the chip module provided by the present application comprises: providing an optical sensing chip, the optical sensing chip having opposite first and second surfaces, the first surface having a pad and a sensing area formed therein; etching the second surface of the optical sensing chip to form a plurality of light vias corresponding to the sensing area in the optical sensing chip for conducting light signals to the sensing area; filling a light-transmitting layer in the light vias; forming a conductive structure on the same side of the second surface, the conductive structure being connected to the pad; and forming an optical structure above the light-transmitting layer.

[0007] Optionally, it further comprises: providing a substrate, the substrate having a circuit board fixed on the surface thereof, the circuit board having an opening exposing part of the surface of the substrate; fixing the first surface of the optical sensing chip having the optical structure and the conductive structure formed thereon to the surface of the substrate at the bottom of the opening; and forming an electrical connection between the conductive structure of the optical sensing chip and the circuit board by wire bonding.

[0008] Optionally, the method for forming the conductive structure comprises: etching the second surface of the optical sensing chip to form a groove, the bottom of the groove exposing the pad of the optical sensing chip; forming an electrical connection layer covering at least the bottom and / or part of the sidewall of the groove, the electrical connection layer being electrically connected to the pad.

[0009] Optionally, the method for forming the conductive structure comprises: etching the second surface of the optical sensing chip to form a conductive via, the bottom of the conductive via exposing the pad of the optical sensing chip; forming an electrical connection layer covering the inner wall of the conductive via.

[0010] Optionally, the sensing region comprises a plurality of discrete sub-sensing regions, and the light via corresponds to the sub-sensing region one by one.

[0011] Optionally, the method further comprises: forming a protection structure around the optical structure on the second surface of the optical sensing chip, the top of the protection structure being higher than the top of the optical structure.

[0012] Optionally, the optical sensing chip is located in a wafer; after the conductive structure and the optical structure are formed in each optical sensing chip in the wafer, the wafer is cut to obtain a single optical sensing chip.

[0013] The technical scheme of the present application further provides a chip module, comprising: an optical sensing chip, the optical sensing chip having opposite first and second surfaces, the first surface being provided with a pad and a sensing region; a plurality of light vias located in the optical sensing chip, the light vias penetrating through part of the thickness of the optical sensing chip from the second surface, corresponding to the sensing region of the optical sensing chip, for conducting light signals to the sensing region; a light-transmitting layer filled in the light via and an optical structure located above the light-transmitting layer; a conductive structure located on the same side of the second surface of the optical sensing chip, the conductive structure being electrically connected to the pad.

[0014] Optionally, the method further comprises: a substrate; a circuit board fixed on the surface of the substrate, the circuit board having an opening, the opening exposing part of the surface of the substrate; the first surface of the optical sensing chip facing the substrate and being fixed on the surface of the substrate at the bottom of the opening; the conductive structure and the circuit board being electrically connected through a bonding wire.

[0015] Optionally, the conductive structure comprises: a groove in the second surface of the optical sensing chip, the bottom of the groove exposing the pads of the first surface of the optical sensing chip; an electrical connection layer covering at least the bottom and / or part of the sidewall of the groove, the electrical connection layer being electrically connected to the pads; or the conductive structure comprises: a conductive via in the second surface of the optical sensing chip, the bottom of the conductive via exposing the pads of the optical sensing chip; an electrical connection layer covering the inner wall of the conductive via.

[0016] Optionally, an insulating layer is formed between the electrical connection layer and the semiconductor substrate of the optical sensing chip.

[0017] Optionally, the sensing area comprises a plurality of discrete sub-sensing areas, and the optical via corresponds to the sub-sensing area one-to-one.

[0018] Optionally, further comprising a protection structure on the second surface of the optical sensing chip and arranged around the optical structure, and the top of the protection structure is higher than the top of the optical structure.

[0019] The technical scheme of the present application further provides an electronic device comprising the chip module according to any one of the above.

[0020] The forming method of the chip module of the present application forms an optical via in the other side surface of the optical sensing chip opposite to the sensing area, fills the light-transmitting layer in the optical via, and forms the optical structure above the light-transmitting layer, which can directly form the optical structure on the chip surface without using a glass substrate as a carrier, thereby reducing the thickness of the chip module. Moreover, by forming the conductive structure on the side where the optical via is located and connecting to the pads of the optical sensing chip, the signal connection end is led out to the side where the optical structure is located through the conductive structure, which is conducive to forming electrical connection between the chip module and the circuit board through wire bonding in the subsequent process.

[0021] Further, the optical sensing chip is fixed in a flip-chip manner on the surface of a substrate, the surface of the substrate is fixed with a circuit board, and the optical sensing chip is located in an opening of the circuit board, so that the circuit board does not occupy the overall thickness of the chip module, thereby effectively reducing the thickness of the chip module. The electrical connection is formed between the conductive structure and the circuit board through wire bonding process, and the flip-chip soldering process does not occupy the thickness of the chip module by solder, thereby further reducing the thickness of the chip module. BRIEF DESCRIPTION OF DRAWINGS

[0022] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed to be used in the embodiments description will be briefly introduced. Obviously, the drawings in the following description only constitute some embodiments of the present application, and for those skilled in the art, other drawings can be obtained from these drawings without creative labor.

[0023] Figures 1 to 8 A structural schematic diagram of a forming process of a chip module according to an embodiment of the present application is shown in FIG. 1.

[0024] Figures 9 to 12 A structural schematic diagram of a forming process of a chip module according to an embodiment of the present application is shown in FIG. 1.

[0025] Figures 13 to 16 A structural schematic diagram of a forming process of a chip module according to an embodiment of the present application is shown in FIG. 1. DETAILED DESCRIPTION

[0026] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings. Obviously, the described embodiments are only some of the embodiments of the present application, but not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of the present application. In the case of no conflict, each of the following embodiments and technical features can be combined with each other.

[0027] Reference is made to Figures 1 to 8 A structural schematic diagram of a forming process of a chip module according to an embodiment of the present application is shown in FIG. 1.

[0028] Reference is made to Figure 1 An optical sensing chip 100 is provided, which has opposite first and second surfaces 110 and 120. A pad 111 and a sensing area 112 are formed in the first surface 110.

[0029] The first surface 110 can be understood as the front surface of the optical sensing chip 100, and the second surface 120 opposite to the first surface 110 is the back surface of the optical sensing chip 100.

[0030] The bonding pad 111 is formed on the periphery of the sensing region 112, and is connected with the interconnection structure in the optical sensing chip 100, and serves as the connection point for signal output. Specifically, as an embodiment, the optical sensing chip 100 comprises a semiconductor substrate, and a dielectric layer formed on the top surface of the semiconductor substrate, the top surface of the dielectric layer is the first surface 110, the bottom surface of the semiconductor substrate is the second surface 120, and the top surface of the semiconductor substrate is formed with a light sensing unit, which can be a CMOS sensing unit or a CCD sensing unit or other photosensitive sensing unit. The dielectric layer is formed with an interconnection structure connected to the light sensing unit, and the bonding pad 111 is located above the interconnection structure and connected with the interconnection structure. Figure 1 The sensing region 112 is only a schematic of the approximate position, and does not represent the actual position and size of the sensing region 112.

[0031] Although Figure 1 In this embodiment, only a single chip structure is shown, but in the actual forming method, the optical sensing chip 100 can be a part of a whole wafer, or a single bare chip obtained after wafer cutting.

[0032] Please refer to Figure 2 The second surface 120 of the optical sensing chip 100 is thinned to a target thickness.

[0033] In order to avoid damage to the first surface 110 of the optical sensing chip 100, and to provide physical support for the optical sensing chip 100, the first surface 110 of the optical sensing chip 100 is fixed to the surface of a temporary carrier 200 before thinning.

[0034] The temporary carrier 200 can be glass, plastic substrate, steel plate, etc., which can provide strong physical support and protect the first surface 110 of the optical sensing chip 100. In this embodiment, the optical sensing chip 100 is a part of a wafer, and the temporary carrier 200 can be a carrier with a size comparable to the wafer, and the whole wafer is fixed to the surface of the temporary carrier 200, so that the second surface 120 of all optical sensing chips 100 in the wafer can be thinned at the same time. In the embodiment of the present application, the optical sensing chip 100 can be fixed to the surface of the temporary carrier 200 by means of an adhesive layer or a bonding process.

[0035] The second surface 120 of the optical sensing chip 100 can be thinned by at least one of etching and chemical mechanical grinding, so that the thickness of the thinned optical sensing chip 100a is a target thickness, to reduce the difficulty of subsequent etching or deposition processes. The target thickness can be at least 40 μm to 60 μm, or even 30 μm, and can be adjusted according to specific requirements. In other embodiments, the thinning step can be omitted when the thickness of the optical sensing chip 100 is small.

[0036] Please refer to Figure 3 The second surface 120 of the optical sensing chip 100a is etched to form a plurality of optical vias 301 corresponding to the sensing region 112 in the thinned optical sensing chip 100a, for conducting optical signals to the sensing region 112.

[0037] Figure 3 In some embodiments, two optical vias 301 are taken as an example. The second surface 120 of the optical sensing chip 100a is etched by a dry etching process to the inside of the semiconductor substrate of the optical sensing chip, to form an optical via 301 penetrating a portion of the thickness of the optical sensing chip 100a. The optical via 301 corresponds to the sensing region 112, so that the optical signal from the optical via 301 that is incident on the bottom of the semiconductor substrate of the optical via 301 can be received by the sensing region 112 to generate an optical sensing signal, i.e., an electrical signal generated by a photoelectric conversion effect. If the thickness of the semiconductor substrate at the bottom of the optical via 301 is too small, it can cause damage to the sensing elements in the optical sensing region 112, resulting in a decrease in the photoelectric conversion capability of the sensing region. If the thickness of the semiconductor substrate at the bottom of the optical via 301 is too large, it can cause excessive loss of optical signals, resulting in a low photoelectric conversion efficiency. In some embodiments, the thickness of the semiconductor substrate at the bottom of the optical via 301 is in the range of 10 μm to 50 μm. Those skilled in the art can adjust the depth of the optical via 301 to adjust the thickness of the semiconductor substrate at the bottom of the optical via 301 according to actual requirements, and embodiments of the present application do not limit this.

[0038] The spacing between adjacent optical vias 301 cannot be too small to avoid crosstalk between optical signals between adjacent optical vias 301. Preferably, the spacing between adjacent optical vias 301 can be greater than twice the thickness of the semiconductor substrate at the bottom of the optical via 301, so that the semiconductor substrate material between adjacent optical vias 301 can provide a better optical isolation effect, so that the optical signal entering the optical via 301 can only be received by the local optical sensing region at the bottom of the optical via 301. A plurality of optical vias 301 form an optical via array.

[0039] In some embodiments, the sensing region 112 is a whole sensing region including a plurality of arrayed sensing units, and only a part of the sensing region at the bottom of the light through hole 301 can receive a light signal to generate a light sensing signal for forming a light sensing image.

[0040] In some embodiments, the sensing region 112 can include a plurality of sub-sensing regions corresponding to the light through hole 301, and the sub-sensing regions are located in the projection region of the corresponding light through hole on the first surface, and each sub-sensing region includes one or more sensing units. Adjacent sub-sensing regions can be isolated by an isolation structure, such as a shallow trench isolation structure, to avoid crosstalk between the light sensing signals (electrical signals) generated by the sub-sensing regions.

[0041] Please refer to Figure 4 , the light through hole 301 (please refer to Figure 3 ) is filled with a light-transmitting layer 401.

[0042] The material of the light-transmitting layer 401 can be a material with a self-leveling effect, which can be self-filled in the light through hole 301 and form a flat surface covering the second surface 120 at a position slightly higher than the second surface 120. The light-transmitting layer 401 can be formed in the light through hole 301 and the second surface 120 of the chip by at least one or several of vacuum spin coating, multiple spin coating, or printing.

[0043] In this embodiment, after the light-transmitting layer 401 forms a flat surface through the self-leveling effect, the surface of the light-transmitting layer 401 is further processed by mechanical or chemical mechanical polishing, etching, etc., to make it more flat, so as to reduce the diffuse reflection of the light-transmitting layer 401 to the incident light and improve the optical performance; further, the height of the light-transmitting layer 401 can be adjusted to remove the part higher than the second surface 120, so that the light-transmitting layer 401 is only located in the light through hole 401.

[0044] Those skilled in the art can adjust the thickness of the light-transmitting layer 401 according to specific needs, so that the surface of the light-transmitting layer 401 is flush with the second surface 120, or covers the second surface 120.

[0045] Please refer to Figure 5 , etching the second surface 120 of the optical sensing chip 100a to form a trench.

[0046] In this embodiment, the semiconductor substrate of the optical sensing chip 100a is etched from the second surface 120 to form a groove. The groove is located at the edge of the optical sensing chip 100a and corresponds to the position of the pad 111. Specifically, the groove includes a first groove 501 and a second groove 502 located above the first groove 501 and in communication with the first groove 501. The width of the second groove 502 is greater than the width of the first groove 501. The bottom of the first groove 501 exposes the pad 111. A conductive structure is subsequently formed in the groove.

[0047] Please refer to Figure 6 An electrical connection layer 602 is formed in the groove to connect the pad 111.

[0048] The electrical connection layer 602 is connected to the pad 111 and used to lead the pad 111 out to the side of the second surface 120 of the optical sensing chip 100a.

[0049] In this embodiment, an insulating layer 601 is further formed between the electrical connection layer 602 and the semiconductor substrate of the optical sensing chip. The formation method of the insulating layer 601 and the electrical connection layer 602 includes: forming an insulating material layer covering the back surface of the optical sensing chip, patterning the insulating material layer to form an insulating layer 601 covering the sidewall of the first groove 501 and the step surface at the junction of the first groove 501 and the second groove 502, the insulating layer 601 exposing the surface of the pad 111; forming an electrical connection material layer covering the back surface of the optical sensing chip 100a, patterning the electrical connection material layer to form an electrical connection layer connecting the pad 111. In this embodiment, the electrical connection layer 602 covers the surface of the pad 111 in the inner wall of the first groove 501 and the surface of the insulating layer 601.

[0050] The electrical connection layer 602 includes a re-distribution layer (RDL). The material used can be copper, gold, silver, or aluminum, etc. The electrical connection line pattern in the electrical connection layer 602 can be designed according to the distribution position of the pad 111 and the signal connection needs.

[0051] Please refer to Figure 7 An optical structure is formed on the top of the light-transmitting layer 401.

[0052] In this embodiment, the optical structure is a microlens 702. The microlens 702 is formed on each light through hole filled with the light-transmitting layer 401. The microlens 702 corresponds to the light through hole one by one and constitutes a microlens array. The size of the microlens 702 can be slightly larger than the size of the light through hole. In other embodiments, a microlens with a larger size can be formed so that each microlens corresponds to multiple light through holes below.

[0053] In other embodiments, the optical structure can further include a filter layer, an anti-reflection layer, or the like functional layer. In some embodiments, a filter layer can be coated on the surface of the formed microlens 702 to filter light rays of an unwanted waveband. In other embodiments, a filter material can also be doped in the material of the microlens 702, so that the microlens 702 itself has a filtering effect; in other embodiments, a filter material can also be doped in the light-transmitting layer 401, so that the light-transmitting layer 401 has a filtering effect, and the microlens 702 can be formed after the filter layer is formed on the surface of the light-transmitting layer 401. In other embodiments, an anti-reflection layer can also be formed on the surface of the microlens 702 and / or the interface between the light-transmitting layer 401 and the microlens 702 to improve the optical performance of the formed optical sensor chip.

[0054] The material of the microlens 702 can be a photoresist, a resin, or the like organic polymer material, which is formed by printing or etching. Since etching and high-temperature processes are used in the process of forming the conductive structure, the optical structure needs to be formed after the formation of the electrically connecting layer 602.

[0055] In this embodiment, a light-blocking layer 701 is also formed on the surface of the semiconductor substrate between adjacent light vias, to avoid part of the light signals of a waveband with relatively high transmittance, such as infrared light, from penetrating into the sensing area outside the bottom of the light via. In other embodiments, the thickness of the semiconductor substrate can also be adjusted so that the semiconductor substrate itself can block the light signals, without the need to additionally form a light-blocking layer.

[0056] The above processes can be performed at the wafer level, which can reduce the alignment difficulty of each step, especially the alignment difficulty of forming the optical structure, especially the alignment difficulty of forming the microlens. The above method can control the alignment accuracy of the microlens to be within 2 μm, thereby improving the yield and production capacity. Moreover, the optical structure is directly formed on the surface of the optical sensor chip, without the need to use glass as the carrier of the optical structure, which can reduce the thickness of the finally formed optical sensor and eliminate the patching step.

[0057] After the above steps are completed, the wafer can be peeled off from the temporary carrier 200 and cut to obtain single optical sensor chips 800 (see Figure 8 ).

[0058] Please refer to Figure 8The substrate 810 is provided with the circuit board 820 fixed on the surface of the substrate 810, and the circuit board 820 has an opening 821 exposing part of the surface of the substrate 810. The first surface 110 of the processed optical sensor chip 800 is fixed on the surface of the substrate 810 at the bottom of the opening 821, and the electrically conductive structure of the optical sensor chip 800 is connected to the circuit board 820 by wire bonding.

[0059] The substrate 810 is a plate material with mechanical strength, such as a reinforced steel plate, a glass substrate, a ceramic substrate, etc., which is used to provide mechanical support for the optical sensor chip 800. The substrate 810 can also be a hard circuit board, such as a BT substrate, an FR-4 substrate, etc., which provides mechanical support and signal transmission at the same time. The circuit board 820 is a flexible circuit board (FPCB) with low thickness, and due to its flexibility, it can improve the flexibility of the connection between the chip module and external devices.

[0060] The circuit board 820 has an opening 821 for accommodating the optical sensor chip 800, so that the circuit board 820 no longer occupies the entire thickness of the chip module, thereby reducing the thickness of the entire chip module.

[0061] The circuit board 820 and the optical sensor chip 800 are fixed on the surface of the substrate 810 by the adhesive layer 811. The electrically conductive layer 602 of the optical sensor chip 800 is connected to the pad 822 on the surface of the circuit board 820 by bonding wires, so that the optical sensor chip 800 and the circuit board 820 are electrically connected.

[0062] Please refer to Figures 9 to 12 for the structure of the chip module of another embodiment of the present application.

[0063] Please refer to Figure 9 , in Figure 4 On the basis of the structure, the second surface 120 of the optical sensor chip 100a is etched to form a conductive via hole 901, and the bottom of the conductive via hole 901 exposes the pad 111.

[0064] Please refer to Figure 10 , an insulating layer 1001 covering the sidewall of the conductive via hole 901 is formed, an electrically conductive layer 1002 covering the surface of the pad 111 at the bottom of the conductive via hole 901 and the surface of the insulating layer 1001 is formed, and then an optical structure 1003 is formed on the top of the light-transmitting layer 401.

[0065] The insulating layer 1001 also covers the surface of the semiconductor substrate between the light-transmitting layers 401 in the adjacent optical via holes of the optical sensing chip, as a light-blocking layer. In other embodiments, the insulating layer 1001 can also cover only the sidewalls of the conductive via hole 901.

[0066] The electrical connection layer 1002 further includes an electrical connection pin on the second surface 120, as a bonding pin for connection with a circuit board.

[0067] Please refer to Figure 11a and Figure 11b to form a protective structure 1101 surrounding the optical structure 1003, and the top of the protective structure 1101 is higher than the top of the optical structure 1003. Among them, Figure 11b is a top view schematic diagram of the optical structure 1003 and the protective structure 1101.

[0068] The protective structure 1101 is used to protect the optical structure 1003, and can play a protective and supporting role around the optical structure 1003.

[0069] Please refer to Figure 11b In this embodiment, the protective structure 1101 surrounds the optical structure 1003 to form a circular space. In other embodiments, the edge of the protective structure 1101 towards the optical structure 1003 can also surround a triangle, square, trapezoid or polygon, etc. shape, which can be adjusted according to the optical path requirement to improve the optical imaging characteristics of the optical structure 1003. In order to avoid contact with the optical structure 1003 or too close distance from the optical structure 1003 affecting the imaging of the optical structure 1003, the lateral distance between the protective structure 1101 and the optical structure 1003 needs to be greater than 1 μm.

[0070] Two or more optical structures 1003 can also be formed in the space surrounded by the protective structure 1101.

[0071] In order to play a sufficient supporting and protective role, the distance between the top of the protective structure 1101 and the top of the optical structure 1003 can be between 1 μm and 2 mm, which can be reasonably adjusted by those skilled in the art according to the actual situation.

[0072] The material of the protective structure 1101 is a polymer material such as photoresist or resin, which can also be metal or other mechanical materials, which is easy to shape and has less influence on light propagation. The material of the protective structure 1101 has a large Young's modulus and a certain hardness, and is not easy to deform, so as to play a strong supporting role.

[0073] In this embodiment, the material of the protection structure 1101 is a photoresist layer. After forming the photoresist layer on the surface of the optical sensing chip by a spin coating process, the photoresist layer is patterned to form the protection structure 1101.

[0074] In other embodiments, the protection structure 1101 can also be made of a metal or dielectric layer, etc. The patterned protection structure 1101 can be formed by deposition and etching processes.

[0075] In other embodiments, the protection structure 1101 can also be formed by a screen printing process.

[0076] The temporary carrier 200 is removed to obtain the processed optical sensing chip 1200 (see Figure 12 ).

[0077] Please refer to Figure 12 , a substrate 1210 is provided, and the surface of the substrate 1210 is fixed with a circuit board 1220. The circuit board 1220 has an opening 1221, and the opening 1221 exposes part of the surface of the substrate 1210. The first surface of the processed optical sensing chip 1200 is fixed to the surface of the substrate 1210 at the bottom of the opening 1221, and electrical connection is formed between the conductive structure of the optical sensing chip 1200 and the circuit board 1220 by wire bonding.

[0078] The optical sensing chip 1200 is located in the opening 1221, which can reduce the thickness of the entire chip module.

[0079] The bonding wire 1223 connects the pad 1222 of the circuit board 1220 and the electrical connection layer 1002 of the conductive structure of the optical sensing chip 1200, realizing electrical connection between the optical sensing chip 1200 and the circuit board 1220.

[0080] The circuit board 1220, the optical sensing chip 1200, and the substrate 1210 are fixed by the adhesive layer 1211.

[0081] Please refer to Figures 13 to 16 , a structural schematic diagram of the forming process of the chip module of another embodiment of the application.

[0082] Please refer to Figure 13 , based on the Figure 4 structure, the second surface 120 of the optical sensing chip 100a is etched to form a groove 1301, and the pad 111 of the optical sensing chip is exposed at the bottom of the groove 1301. The groove 1301 is located at the edge of the optical sensing chip, and only has a single inclined side wall, and the other side is in communication with the outside of the chip.

[0083] Referring to Figure 14 An insulating layer 1401 is formed to cover the sidewalls of the trenches 1301, and an electrically connecting layer 1402 is formed to cover the insulating layer 1401 and the surface of the pads 111 in the bottom of the trenches 1301. After the electrically connecting layer 1402 is formed, an optical structure 1403 is formed to cover the light-transmitting layer 401.

[0084] The insulating layer 1401 also covers the semiconductor substrate between adjacent light-transmitting layers, as a light-blocking layer.

[0085] Referring to Figure 15 A protective structure 1501 is formed to surround the optical structure 1403. The protective structure 1501 also covers the electrically connecting layer 1402, for protecting the electrically connecting layer 1402. Part of the electrically connecting layer 1402 is exposed on the second surface 120 of the optical sensing chip, as a pin for connecting with a circuit board later.

[0086] Referring to Figure 16 After the temporary carrier 200 is removed, the optical sensing chip 1600 is fixed on a surface of a substrate 1610, which is provided with a circuit board 1620 having an opening 1621. The optical sensing chip 1600 is arranged in the opening 1621, and the electrically connecting layer 1402 is electrically connected with the circuit board 1620 by wire bonding, thereby forming a chip module. Specifically, the bonding wire 1623 connects the electrically connecting layer of the optical sensing chip 1600 and the pads 1622 of the circuit board 1620.

[0087] The method for forming the chip module forms a light via in the other side surface of the optical sensing chip opposite to the sensing region, fills the light-transmitting layer in the light via, and forms the optical structure above the light-transmitting layer. The optical structure can be directly formed on the surface of the chip, without using a glass substrate as a carrier, so that the thickness of the chip module can be reduced. Moreover, the conductive structure is formed on the side where the light via is located, and is connected to the pads of the optical sensing chip. The signal connection end is led out to the side where the optical structure is located through the conductive structure, which is conducive to the subsequent electrical connection with the circuit board by wire bonding.

[0088] Further, the optical sensing chip is fixed on the surface of the substrate in an inverted manner, and the circuit board is fixed on the surface of the substrate. The optical sensing chip is located in the opening of the circuit board, so that the circuit board does not occupy the overall thickness of the chip module, and the thickness of the chip module can be effectively reduced. The electrically connecting layer is electrically connected with the circuit board by wire bonding, and the inverted soldering process does not occupy the thickness of the chip module by solder, so that the thickness of the chip module can be further reduced.

[0089] The embodiment of the present application also provides a chip module.

[0090] Please refer to Figure 8 Fig. 1 is a structural schematic diagram of a chip module according to the present application.

[0091] In the embodiment, the chip module comprises: an optical sensing chip 800, the optical sensing chip 800 has opposite first and second surfaces, a pad 111 and a sensing region 112 are formed in the first surface 110; a plurality of light vias are located in the optical sensing chip 800, the light vias penetrate through a part of thickness of the optical sensing chip from the second surface, correspond to the sensing region 112 of the optical sensing chip, and are used for conducting light signals to the sensing region; a light-transmitting layer 401 filled in the light vias and an optical structure located above the light-transmitting layer 401; a conductive structure located on the same side of the second surface of the optical sensing chip, the conductive structure is connected to the pad 111.

[0092] In some embodiments, the sensing region 112 is a whole sensing region, comprises a plurality of array-arranged sensing units, only part of the sensing region located at the bottom of the light via 301 can receive light signals, thereby generating light sensing signals, and is used for forming a light sensing image.

[0093] In some embodiments, the sensing region 112 can comprise a plurality of sub-sensing regions, one-to-one corresponding to the light vias 301, and the sub-sensing regions are located in the projection region of the corresponding light vias on the first surface, and each sub-sensing region comprises one or more sensing units. Adjacent sub-sensing regions can be isolated by an isolation structure, for example, a shallow trench isolation structure, etc., to avoid crosstalk between light sensing signals (electrical signals) generated by each sub-sensing region.

[0094] The conductive structure comprises: a groove located in the second surface of the optical sensing chip 800. The groove is located at the edge of the optical sensing chip 100a and corresponds to the position of the pad 111. Specifically, the groove comprises a first groove 501 and a second groove 502 located above the first groove 501 and communicating with the first groove 501, the width of the second groove 502 is greater than the width of the first groove 501, and the bottom of the first groove 501 exposes the pad 111. The conductive structure further comprises: an electrical connection layer 602 covering the bottom and sidewall of the second groove, the electrical connection layer 602 is electrically connected to the pad 111. An insulating layer 601 is further formed between the electrical connection layer 5601 and the semiconductor substrate.

[0095] The chip module further comprises a substrate 810, a circuit board 820 fixed on the surface of the substrate 810, the circuit board 820 having an opening 821 exposing part of the surface of the substrate 810, the first surface 110 of the optical sensing chip 800 facing the substrate 810, the surface of the substrate 810 at the bottom of the opening 821, and the electrically conductive structure having an electrically connecting layer 602 electrically connected to the bonding wire 823 between the pad 822 of the circuit board 820.

[0096] In this embodiment, the optical structure is a microlens 702, and the microlens 702 is formed on each light through hole filled with the light-transmitting layer 401, the microlens 702 corresponding to the light through hole one by one, constituting a microlens array. In other embodiments, the optical structure can also include a filtering layer, an anti-reflection layer, and other functional layers.

[0097] In this embodiment, the surface of the semiconductor substrate between adjacent light through holes is further provided with a light shielding layer 701 to avoid part of the light signal with a higher transmittance band, such as infrared light, from penetrating into the sensing area outside the bottom of the light through hole. In other embodiments, the thickness of the semiconductor substrate can be adjusted so that the semiconductor substrate itself can shield the light signal, without the need to additionally form a light shielding layer.

[0098] Please refer to Figure 12 for the structural schematic diagram of the chip module of another embodiment of the present application.

[0099] In this embodiment, the chip module comprises an optical sensing chip 1200, and the electrically conductive structure of the optical sensing chip comprises a conductive via penetrating through the optical sensing chip 1200 from the back surface of the optical sensing chip 1200 to the surface of the pad 111, an insulating layer 1001 covering the sidewall of the conductive via, and an electrically connecting layer 1002 covering the insulating layer 1001 in the conductive via and the surface of the pad 111.

[0100] The light-transmitting layer 401 in the light through hole in the optical sensing chip 1200 is provided with an optical structure 1003. The insulating layer 1001 also covers the surface of the semiconductor substrate between the light-transmitting layers 401 in the adjacent light through holes of the optical sensing chip, as a light shielding layer.

[0101] The electrically connecting layer 1002 further comprises an electrically connecting pin on the second surface 120, as a bonding pin for connecting with the circuit board.

[0102] The optical sensing chip 1200 further comprises a protection structure 1101 arranged around the optical structure 1003, and the top of the protection structure 1101 is higher than the top of the optical structure 1003. The protection structure 1101 is used for protecting the optical structure 1003, and can play a protection and support role around the optical structure 1003.

[0103] The chip module further comprises a substrate 1210, and a circuit board 1220 is fixed on the surface of the substrate 1210. The circuit board 1220 has an opening 1221, which exposes part of the surface of the substrate 1210. The first surface 110 of the optical sensing chip 1200 is fixed on the surface of the substrate 1210 at the bottom of the opening 1221. The bonding wire 1223 is used to form an electrical connection between the pad 1222 of the circuit board 1220 and the conductive structure of the optical sensing chip 1200.

[0104] The circuit board 1220, the optical sensing chip 1200 and the substrate 1210 are fixed by the adhesive layer 1211.

[0105] Please refer to Figure 16 for the structural schematic diagram of the chip module of another embodiment of the application.

[0106] In this embodiment, the chip module comprises an optical sensing chip 1600, and the conductive structure of the optical sensing chip 1600 comprises a groove 1301 penetrating through the optical sensing chip 1200 from the back surface of the optical sensing chip 1200 to the surface of the pad 111. The groove 1301 is located at the edge of the optical sensing chip, has only one side of the inclined side wall, and the other side is in communication with the outside of the chip; an insulating layer 1401 covering the side wall of the groove 1301, and an electrical connection layer 1402 covering the insulating layer 1401 and the bottom of the groove 1301. The insulating layer 1401 also covers the semiconductor substrate between the adjacent light-transmitting layers, as a light shielding layer.

[0107] The optical sensing chip 1600 further comprises an optical structure 1403 covering the light-transmitting layer 401 and a protection structure 1501 arranged around the optical structure 1403. The protection structure 1501 also covers the electrical connection layer 1402, and is used for protecting the electrical connection layer 1402. Part of the electrical connection layer 1402 is exposed on the second surface 120 of the optical sensing chip, as a pin for subsequent connection with the circuit board.

[0108] The chip module further comprises a substrate 1610, a circuit board 1620 is fixed on the surface of the substrate 1610, the circuit board 1620 has an opening 1621, the opening 1621 exposes part of the surface of the substrate 1610, the first surface 110 of the optical sensing chip 1600 is fixed on the surface of the substrate 1610 at the bottom of the opening 1621, and the bonding wire 1623 is used to form an electrical connection between the pad 1622 of the circuit board 1620 and the electrical connection layer 1402 of the optical sensing chip 1600. The circuit board 1620, the optical sensing chip 1600 and the substrate 1610 are fixed by the adhesive layer 1611.

[0109] Other embodiments of the present application also provide an electronic device comprising the above chip module.

[0110] The chip module can be used as an under-screen fingerprint identification device of an electronic device, the optical structure of the optical sensing chip of the chip module is directed towards the fingerprint detection position of the electronic device, the reflected light of the fingerprint surface passes through the optical sensing structure and enters the light through hole, and the sensing area at the bottom of the light through hole receives the reflected light to form a corresponding sensing image. Although multiple local images corresponding to the position of the light through hole are formed, the fingerprint pattern features in the local image can still be obtained, so that fingerprint identification is realized.

[0111] In other embodiments, the chip module can also be used as other optical sensing devices, for example, as a sensing device for face recognition, by obtaining multiple local images of the face, extracting feature information at multiple positions of the face, and then realizing face recognition.

[0112] Since the thickness of the chip module is low, the thickness of the electronic device is reduced, and the difficulty of device layout in the electronic device is reduced.

[0113] The above description is only an embodiment of the present application, and does not limit the patent scope of the present application, any equivalent structure or equivalent process transformation using the content of the specification and drawings, for example, the mutual combination of technical features between embodiments, or direct or indirect application in other related technical fields, are also included in the patent protection scope of the present application.

Claims

1. A method of forming a chip module, characterized by, The application provides an optical sensing chip including a semiconductor substrate, a first surface and a second surface of the optical sensing chip, a pad and a sensing area formed in the first surface, and a plurality of light vias formed in the optical sensing chip by etching the second surface of the optical sensing chip, the light vias penetrating through a partial thickness of the optical sensing chip and corresponding to the sensing area, and conducting light signals to the sensing area, wherein the thickness of the semiconductor substrate at the bottom of the light vias ranges from 10 μm to 50 μm, and the interval between adjacent light vias is greater than twice the thickness of the semiconductor substrate at the bottom of the light vias. The application further provides a method for manufacturing the optical sensing chip, including the following steps: providing an optical sensing chip including a semiconductor substrate, a first surface and a second surface of the optical sensing chip, a pad and a sensing area formed in the first surface, and a plurality of light vias formed in the optical sensing chip by etching the second surface of the optical sensing chip, the light vias penetrating through a partial thickness of the optical sensing chip and corresponding to the sensing area, and conducting light signals to the sensing area, wherein the thickness of the semiconductor substrate at the bottom of the light vias ranges from 10 μm to 50 μm, and the interval between adjacent light vias is greater than twice the thickness of the semiconductor substrate at the bottom of the light vias. The application further provides a method for manufacturing the optical sensing chip, including the following steps: providing an optical sensing chip including a semiconductor substrate, a first surface and a second surface of the optical sensing chip, a pad and a sensing area formed in the first surface, and a plurality of light vias formed in the optical sensing chip by etching the second surface of the optical sensing chip, the light vias penetrating through a partial thickness of the optical sensing chip and corresponding to the sensing area, and conducting light signals to the sensing area, wherein the thickness of the semiconductor substrate at the bottom of the light vias ranges from 10 μm to 50 μm, and the interval between adjacent light vias is greater than twice the thickness of the semiconductor substrate at the bottom of the light vias. The application further provides a method for manufacturing the optical sensing chip, including the following steps: providing an optical sensing chip including a semiconductor substrate, a first surface and a second surface of the optical sensing chip, a pad and a sensing area formed in the first surface, and a plurality of light vias formed in the optical sensing chip by etching the second surface of the optical sensing chip, the light vias penetrating through a partial thickness of the optical sensing chip and corresponding to the sensing area, and conducting light signals to the sensing area, wherein the thickness of the semiconductor substrate at the bottom of the light vias ranges from 10 μm to 50 μm, and the interval between adjacent light vias is greater than twice the thickness of the semiconductor substrate at the bottom of the light vias. The application further provides a method for manufacturing the optical sensing chip, including the following steps: providing an optical sensing chip including a semiconductor substrate, a first surface and a second surface of the optical sensing chip, a pad and a sensing area formed in the first surface, and a plurality of light vias formed in the optical sensing chip by etching the second surface of the optical sensing chip, the light vias penetrating through a partial thickness of the optical sensing chip and corresponding to the sensing area, and conducting light signals to the sensing area, wherein the thickness of the semiconductor substrate at the bottom of the light vias ranges from 10 μm to 50 μm, and the interval between adjacent light vias is greater than twice the thickness of the semiconductor substrate at the bottom of the light vias. The application further provides a method for manufacturing the optical sensing chip, including the following steps: providing an optical sensing chip including a semiconductor substrate, a first surface and a second surface of the optical sensing chip, a pad and a sensing area formed in the first surface, and a plurality of light vias formed in the optical sensing chip by etching the second surface of the optical sensing chip, the light vias penetrating through a partial thickness of the optical sensing chip and corresponding to the sensing area, and conducting light signals to the sensing area, wherein the thickness of the semiconductor substrate at the bottom of the light vias ranges from 10 μm to 50 μm, and the interval between adjacent light vias is greater than twice the thickness of the semiconductor substrate at the bottom of the light vias. The application further provides a method for manufacturing the optical sensing chip, including the following steps: providing an optical sensing chip including a semiconductor substrate, a first surface and a second surface of the optical sensing chip, a pad and a sensing area formed in the first surface, and a plurality of light vias formed in the optical sensing chip by etching the second surface of the optical sensing chip, the light vias penetrating through a partial thickness of the optical sensing chip and corresponding to the sensing area, and conducting light signals to the sensing area, wherein the thickness of the semiconductor substrate at the bottom of the light vias ranges from 10 μm to 50 μm, and the interval between adjacent light vias is greater than twice the thickness of the semiconductor substrate at the bottom of the light vias.

2. The method of forming a chip module according to claim 1, wherein The application further provides a method for manufacturing the optical sensing chip, including the following steps: providing an optical sensing chip including a semiconductor substrate, a first surface and a second surface of the optical sensing chip, a pad and a sensing area formed in the first surface, and a plurality of light vias formed in the optical sensing chip by etching the second surface of the optical sensing chip, the light vias penetrating through a partial thickness of the optical sensing chip and corresponding to the sensing area, and conducting light signals to the sensing area, wherein the thickness of the semiconductor substrate at the bottom of the light vias ranges from 10 μm to 50 μm, and the interval between adjacent light vias is greater than twice the thickness of the semiconductor substrate at the bottom of the light vias. The application further provides a method for manufacturing the optical sensing chip, including the following steps: providing an optical sensing chip including a semiconductor substrate, a first surface and a second surface of the optical sensing chip, a pad and a sensing area formed in the first surface, and a plurality of light vias formed in the optical sensing chip by etching the second surface of the optical sensing chip, the light vias penetrating through a partial thickness of the optical sensing chip and corresponding to the sensing area, and conducting light signals to the sensing area, wherein the thickness of the semiconductor substrate at the bottom of the light vias ranges from 10 μm to 50 μm, and the interval between adjacent light vias is greater than twice the thickness of the semiconductor substrate at the bottom of the light vias. The application further provides a method for manufacturing the optical sensing chip, including the following steps: providing an optical sensing chip including a semiconductor substrate, a first surface and a second surface of the optical sensing chip, a pad and a sensing area formed in the first surface, and a plurality of light vias formed in the optical sensing chip by etching the second surface of the optical sensing chip, the light vias penetrating through a partial thickness of the optical sensing chip and corresponding to the sensing area, and conducting light signals to the sensing area, wherein the thickness of the semiconductor substrate at the bottom of the light vias ranges from 10 μm to 50 μm, and the interval between adjacent light vias is greater than twice the thickness of the semiconductor substrate at the bottom of the light vias. The application further provides a method for manufacturing the optical sensing chip, including the following steps: providing an optical sensing chip including a semiconductor substrate, a first surface and a second surface of the optical sensing chip, a pad and a sensing area formed in the first surface, and a plurality of light vias formed in the optical sensing chip by etching the second surface of the optical sensing chip, the light vias penetrating through a partial thickness of the optical sensing chip and corresponding to the sensing area, and conducting light signals to the sensing area, wherein the thickness of the semiconductor substrate at the bottom of the light vias ranges from 10 μm to 50 μm, and the interval between adjacent light vias is greater than twice the thickness of the semiconductor substrate at the bottom of the light vias.

3. The method of claim 1, wherein The application further provides a method for manufacturing the optical sensing chip, including the following steps: providing an optical sensing chip including a semiconductor substrate, a first surface and a second surface of the optical sensing chip, a pad and a sensing area formed in the first surface, and a plurality of light vias formed in the optical sensing chip by etching the second surface of the optical sensing chip, the light vias penetrating through a partial thickness of the optical sensing chip and corresponding to the sensing area, and conducting light signals to the sensing area, wherein the thickness of the semiconductor substrate at the bottom of the light vias ranges from 10 μm to 50 μm, and the interval between adjacent light vias is greater than twice the thickness of the semiconductor substrate at the bottom of the light vias.

4. The method of claim 1, wherein The application further provides a method for manufacturing the optical sensing chip, including the following steps: providing an optical sensing chip including a semiconductor substrate, a first surface and a second surface of the optical sensing chip, a pad and a sensing area formed in the first surface, and a plurality of light vias formed in the optical sensing chip by etching the second surface of the optical sensing chip, the light vias penetrating through a partial thickness of the optical sensing chip and corresponding to the sensing area, and conducting light signals to the sensing area, wherein the thickness of the semiconductor substrate at the bottom of the 5. A chip module, characterized by ​ ​ ​ ​ ​ 6. The chip module according to claim 5, characterized by ​ ​ a circuit board fixed on the surface of the substrate, the circuit board having an opening exposing part of the surface of the substrate; a first surface of the optical sensing chip faces the substrate, and is fixed on the surface of the substrate at the bottom of the opening; an electrical connection is formed between the conductive structure and the circuit board through a bonding wire.

7. The chip module according to claim 6, characterized by the conductive structure comprises: a groove in the second surface of the optical sensing chip, the bottom of the groove exposing a pad of the first surface of the optical sensing chip; an electrical connection layer covering at least the bottom and / or part of the sidewall of the groove, the electrical connection layer being electrically connected to the pad; or, the conductive structure comprises: a conductive via in the second surface of the optical sensing chip, the bottom of the conductive via exposing a pad of the optical sensing chip; an electrical connection layer covering the inner wall of the conductive via.

8. The chip module according to claim 7, characterized by an insulating layer is formed between the electrical connection layer and the semiconductor substrate of the optical sensing chip.

9. The chip module according to claim 5, characterized by the sensing region comprises a plurality of discrete sub-sensing regions, and the optical vias correspond one-to-one to the sub-sensing regions.

10. The chip module according to claim 5, characterized by a protection structure is further included, which is located on the second surface of the optical sensing chip and surrounds the optical structure, and the top of the protection structure is higher than the top of the optical structure.

11. An electronic device, comprising: a chip module as claimed in any one of claims 5 to 10. a chip module as claimed in any one of claims 5 to 10.

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