Patent Publication Number: US-2023155040-A1

Title: Semiconductor packaging including photovoltaic particles having a core-shell structure

Description:
TECHNICAL FIELD 
     This application claims priority from Korean Patent Application No. 10-2021-0155993, filed on Nov. 12, 2021, which is hereby incorporated by reference for all purposes as if fully set forth herein. 
     The present disclosure relates to a semiconductor packaging capable of supplying power by itself by photovoltaic power generation. 
     BACKGROUND 
     A semiconductor package includes a substrate such as a lead frame and a printed circuit board, a semiconductor chip attached to the substrate, a conductive means such as a conductive wire or a bump that connects the semiconductor chip and the substrate for the exchange of electrical signals therebetween, a molding resin molded to protect the semiconductor chip, the conductive means, etc. from the outside, and so on. 
     The semiconductor package manufactured in that way is mounted on a motherboard of an electronic device (mobile phone, laptop, etc.) as a CPU or memory. Most semiconductor packages consume a certain level of power as they are driven based on power supplied to electronic devices. 
     Multiple semiconductor packages as the CPU and the memory are mounted on the motherboard of electronic devices, which is one of the factors in an increase in power consumption. However, in the process of miniaturization of semiconductor packages, the design of a structure where a separate power supply part is connected is reaching its limit, and, in the environment of the Internet of Things (IoT), etc., which requires an independent sensor device and a communication device necessary therefor, a semiconductor package having a semi-permanent power supply device therein is required. 
     SUMMARY 
     The purpose of the present disclosure is to provide a semiconductor package that is capable of supplying power to semiconductors semi-permanently and autonomously by photovoltaic power generation, generates a large amount of power, and is easy to miniaturize. 
     In order to achieve the aforementioned purpose, the semiconductor packaging of the present disclosure includes, as a power supply part, photovoltaic particles having a core-shell structure including a core part and a shell part. 
     Here, the core part and the shell part of the photovoltaic particles may be different electrodes selected from an anode and a cathode. 
     Specifically, the semiconductor packaging may include a substrate, a power generation connection layer positioned on the substrate and including external terminals and the photovoltaic particles, and a semiconductor layer positioned on the power generation connection layer. 
     In this case, the power generation connection layer may include a plurality of photovoltaic particles, the plurality of photovoltaic particles may be connected to each other in series or in parallel, and the power generation connection layer may include the plurality of photovoltaic particles spaced apart from each other. 
     To be specific, the semiconductor layer may include a semiconductor chip and a mold portion surrounding the semiconductor chip, and the mold portion may allow light to pass through itself. 
     A rearrangement layer may be located between the power generation connection layer and the semiconductor layer, and the external terminals and the photovoltaic particles may be formed as a single layer and attached to one surface of the rearrangement layer. 
     In addition, the rearrangement layer may include an extension extending to at least a portion of an upper surface of the semiconductor layer, the photovoltaic particles may be positioned on the extension, and the external terminals and the photovoltaic particles may be formed as a single layer and attached to the other surface of the rearrangement layer as well. 
     Meanwhile, to increase power generation, the semiconductor package may include reflection portions, and the reflection portions may be formed around the power generation connection layer on the substrate. 
     Furthermore, the photovoltaic particles may be positioned around the power generation connection layer. 
     In the semiconductor packaging including the photovoltaic particles having the core-shell structure according to the present disclosure, the semiconductor package can be easily driven only with power generated by itself by virtue of the excellent power production of the photovoltaic particles, thereby overcoming the restrictions on miniaturization of semiconductor packages due to connection with external power sources, and the photovoltaic particles are located between the semiconductor chip and the substrate so that the semiconductor package is easy to miniaturize. 
     In addition, as it is possible to semi-permanently supply power to the semiconductor package by the photovoltaic particles embedded in the semiconductor package, existing problems such as deletion of a semiconductor memory due to cut-off external power can be solved. 
     Furthermore, voltage and current required for semiconductors can be easily obtained by the photovoltaic particles that can be easily connected in series or in parallel, which are power sources of the semiconductor packaging. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    shows that a first electrode and a second electrode of a photovoltaic particle according to an embodiment of the present disclosure are formed in the same direction. 
         FIG.  2    shows that the first electrode and the second electrode of the photovoltaic particle according to an embodiment of the present disclosure are formed in opposite directions. 
         FIG.  3    is a cross-sectional view schematically showing main components of a semiconductor packaging according to an embodiment of the present disclosure. 
         FIG.  4    is a cross-sectional view conceptually showing a semiconductor chip  11  and a mold portion  12  that surrounds and protects the semiconductor chip in a semiconductor layer  10  according to an embodiment of the present disclosure. 
         FIG.  5    is a cross-sectional view showing a structure in which a rearrangement layer  30  is formed according to an embodiment of the present disclosure. 
         FIG.  6    is a cross-sectional view showing a structure in which an extension  31  of the rearrangement layer  30  is formed according to an embodiment of the present disclosure. 
         FIG.  7    is a cross-sectional view showing a structure in which power generation connection layers  20  are formed on both sides of the rearrangement layer  30  according to an embodiment of the present disclosure 
         FIG.  8    is a cross-sectional view showing a structure in which reflection portions  90  are formed according to an embodiment of the present disclosure. 
         FIG.  9    is a cross-sectional view showing a structure in which the reflection portions  90  are formed and the power generation connection layers  20  are formed on both sides of the rearrangement layer  30  according to an embodiment of the present disclosure. 
         FIG.  10    is a bottom view showing an embodiment of the arrangement of external terminals  40  and the photovoltaic particles  50  in the power generation connection layer  20 . 
     
    
    
     DETAILED DESCRIPTION 
     Interpretation of terms or words used in this specification and the accompanying claims should not be limited to ordinary or dictionary meanings, and the terms or words should be interpreted with meanings consistent with the technology of the present disclosure based on the principle that an inventor can appropriately define meanings of terms to best describe his/her invention. 
     Accordingly, features shown in the embodiments and manufacturing examples described in the specification are only the most preferred embodiments of the present disclosure, and do not show all of the technology of the present disclosure. Therefore, it should be understood that the features may be substituted with various equivalents and modifications at the time of filing the present application. 
     Hereinafter, the embodiments of the present disclosure will be described in detail with reference to the drawings so that a person having ordinary skill in the technical field to which the present disclosure belongs can easily perform the embodiments. However, the present disclosure may be embodied in several different forms and is not limited to the manufacturing examples and embodiments described herein. 
     A semiconductor packaging according to an aspect of the present disclosure may be characterized by including, as a power supply part, photovoltaic particles having a core-shell structure including a core part and a shell part, and it may be possible to drive the semiconductor packaging even in an environment without a separate external power source. Therefore, of course, a separate battery, etc. may be used to additionally supply power to the semiconductor packaging. 
     The photovoltaic particles used as the power supply part of the semiconductor packaging of the present disclosure may not be a typical flat solar cell, but may have a three-dimensional shape and the core-shell structure including the core part and the shell part.  FIGS.  1  and  2    respectively show the structure of the photovoltaic particle according to an embodiment of the present disclosure, and  FIG. ( a )  of each of  FIGS.  1  and  2    shows the outside of the photovoltaic particle while  FIG. ( b )  of each of  FIGS.  1  and  2    is a cross-sectional view showing the inside as well. Referring to  FIG.  1   , the photovoltaic particle  50   a  may include the core part  52  and the shell part  51  formed outside the core part  52 . In this case, the shell part  51  may not completely cover the outside of the core part  52 , and the core part  52  may be exposed on one side. As a result, a first electrode  53  may be formed. In addition, a second electrode  54  electrically connected to the shell part  51  and insulated from the core part  52  may be formed. Here, a separate insulating layer  55  may be formed in the second electrode  54  for the insulation from the core part  52 , but a structure where the second electrode  54  is in contact only with the shell part  51  as shown in  FIG. ( b )  of  FIG.  1    may also be possible. Furthermore, when the second electrode  54  is formed in the same direction as the first electrode as in the embodiment in  FIG.  1   , it may have a ring shape.  FIG.  1    shows a structure in which both the first electrode  53  and the second electrode  54  are formed in the same direction on one side of the photovoltaic particle  50   a  according to an embodiment of the present disclosure, and  FIG.  2    shows a structure in which the second electrode  54  of the photovoltaic particle  50   b  is formed in a direction opposite to the direction in which the first electrode  53  is formed. As long as the second electrode  54  of the photovoltaic particle according to an embodiment of the present disclosure is insulated from the core part, it may be formed at any position on the surface of the shell part  51  without limitation in direction. The embodiment of the photovoltaic particle in  FIG.  1    may be applied to a structure in which an anode and a cathode need to be formed on the same surface as the power supply part of the semiconductor packaging, and the embodiment of the photovoltaic particle in  FIG.  2    may be applied to a structure in which an anode and a cathode need to be formed on opposite surfaces as the power supply part of the semiconductor packaging. 
     The core part  52  and the shell part  51  of the photovoltaic particle  50  may form the first electrode  53  and the second electrode  54 , respectively, and, specifically, the core part  52  and the shell part  51  may form different electrodes selected from an anode and a cathode. For example, the core part  52  may include P-type or N-type silicon, and the shell part  51 , which is a diffusion layer forming a P-N junction, may be formed outside the core part  52 . The core part  52  may further include a P-type or N-type dopant. 
     For example, the photovoltaic particle  50  may have a structure where the core part  52  is formed of the P-type silicon and the shell part  51  that is an N-type diffusion layer is formed on the surface of the core part  52 . In this case, the shell part  51  may be prepared by performing a doping process. POCl 3 , H 3 PO 4 , etc. containing a group 5 element may be diffused into the core part  52  made of the P-type silicon at a high temperature. As a result, the shell part  51  that is the N-type diffusion layer may be formed. In addition, the core part  52  may have a structure in which it is made of silicon as well as a structure in which an insulating ball is coated with silicon. The insulating ball may be made of various materials such as glass and ceramic. However, not limited to the above-mentioned example, the P-type and N-type semiconductors of the core part  52  and the shell part  51  may be formed in reverse, so the core part  52  may be formed as an N-type semiconductor while the shell part  51  may be formed as a P-type semiconductor. 
     The photovoltaic particle  50  may be capable of generating power not only with ultraviolet light but also with photons with weak energy such as visible light and infrared light. That is, since the power generation source of the photovoltaic particle  50  may not be limited to sunlight, the photovoltaic particle  50  may be capable of generating power indoors as well. 
       FIG.  3    schematically shows the main components of the semiconductor packaging according to an embodiment of the present disclosure. Referring to  FIG.  3   , to describe the structure of the semiconductor packaging in detail, the semiconductor packaging may further include a substrate  60 , a power generation connection layer  20  positioned on the substrate  60 , and a semiconductor layer  10  positioned on the power generation connection layer  20  The power generation connection layer  20  may mean a layer that generates electric power by itself and electrically connects the semiconductor layer  10  and the substrate  60 . Specifically, the power generation connection layer  20  is characterized by including external terminals that electrically connect the semiconductor layer  10  and the substrate  60  to transmit signals of semiconductors and the photovoltaic particles  50  capable of serving as a power supply part of the semiconductor layer  10 . When a conventional photovoltaic flat panel is applied to a semiconductor package, along with the additional process of subdividing a large wafer, the process of connecting a plurality of pieces of the cut wafer in series is necessary since the rated voltage required for a semiconductor is 0.5 V or more, and the process of connecting the pieces of the wafer in parallel to supply a required current is also necessary. However, the process of connecting pieces of a flat wafer is very difficult. However, in the case of the semiconductor package of the present disclosure, the photovoltaic particles  50  may be very easily connected in series and in parallel, and the photovoltaic particles with an excellent power production may be applied to the semiconductor package. Therefore, the semiconductor package of the present disclosure is characterized in that the supply of power and voltage required for the semiconductors may be still possible while the volume of the semiconductor package may be greatly reduced compared to a semiconductor package based on a conventional flat-panel solar cell 
     Since the photovoltaic particles  50  having the core-shell structure in the power generation connection layer  20  may have a three-dimensional structure, absorb light, and produce electricity, it may not be desirable that the photovoltaic particles  50  come in contact with external objects such as another photovoltaic particle or the external terminals except for their own electrodes, and, for this reason, the plurality of photovoltaic particles  50  may be formed to be spaced apart from each other in the power generation connection layer  20 . Furthermore, it may be desirable that the photovoltaic particles  50  and the external terminals  40  are also spaced apart from each other. In the process of designing the power generation connection layer  20  where the external terminals  40  are placed in contact with a signal circuit in the semiconductor layer  10  and the photovoltaic particles  50  are in contact with a power circuit in the semiconductor layer  10 , by virtue of the three-dimensional structure of the photovoltaic particles  50  where it may be possible that the photovoltaic particles  50  are spaced apart from each other, it may be easy to design the arrangement of the external terminals  40  and the photovoltaic particles  50  based on voltage and current required for the semiconductor layer  10 . 
     In the power generation connection layer  20 , the external terminals  40  may be formed in a general ball grid array shape, and the photovoltaic particles  50  may be formed in a ball shape similar to that of the external terminals  40 . In addition, the external terminals  40  and the photovoltaic particles  50  in the ball grid array shape may be formed in a similar size, or the photovoltaic particles  50  may be formed in a slightly smaller size. For example, it may be desirable that the diameter of the photovoltaic particles  50  is approximately 20 % smaller than that of the external terminals  40  since, in general, metals of the external terminals  40  may melt in a high-temperature reflow process and then adhere to a pad of the substrate  60  of the package so that the height of the external terminals tends to be lowered while the photovoltaic particles may not melt or shrink in height during the manufacturing process. However, the size of the photovoltaic particles is not particularly limited. The photovoltaic particles may be applied to a general semiconductor packaging, and, to this end, it may be desirable that the size of the photovoltaic particles is 0.3 to 2.0 mm. 
     The photovoltaic particles  50  located between the substrate  60  and the semiconductor layer  10  may be capable of generating power only with light incident on the side of the power generation connection layer  20 , but they may also use light incident through the semiconductor layer to increase power production.  FIG.  4    conceptually shows a semiconductor chip  11  and a mold portion  12  that surrounds and protects the semiconductor chip as the main components of the semiconductor layer  10 . Referring to  FIG.  4   , a structure of a general semiconductor package may be applied to the connection part between the semiconductor chip  11  and the substrate  60 , so a description thereof will not be provided herein When a light-transmitting material that allows light to pass through the mold portion  12  protecting the semiconductor chip  11  is used in the semiconductor layer  10 , the number of photons supplied to the photovoltaic particles  50  located in the power generation connection layer  20  may be increased, thereby increasing the power production of the power generation connection layer  20 . In addition, it may be desirable that the mold portion is transparent, and various transparent resins such as epoxy-based, urethane-based, silicone-based, acrylic-based, polyimide-based, and PMMA-based resins may be used therefor. 
     A circuit for connecting the plurality of photovoltaic particles  50  in the power generation connection layer  20  in series or in parallel to supply voltage and current required for the semiconductor layer  10  may be included, and a rearrangement layer  30  for aligning the connection terminals  40  and the photovoltaic particles  50  may be additionally disposed.  FIG.  5    conceptually shows the position of the rearrangement layer  30 , and the rearrangement layer  30  may be located between the power generation connection layer  20  and the semiconductor layer  10 . The arrangement of the external terminals  40  and the photovoltaic particles  50  may be fixed by the rearrangement layer  30  and the substrate  60 . In this case, it may be desirable that the external terminals  40  and the photovoltaic particles  50  are formed as a single layer and attached to one surface of the rearrangement layer  30  in order to achieve miniaturization of the semiconductor package and improvement of reliability along with an excellent photovoltaic function by minimizing unnecessary connection parts inside the semiconductor package. 
     The rearrangement layer  30  may serve to electrically connect the individual photovoltaic particles. The position of the rearrangement layer  30  may not be limited to the position between the semiconductor layer  10  and the power generation connection layer  20 , and, in order to increase power generation efficiency, the rearrangement layer  30  may extend outside with the photovoltaic particles attached thereto. For example, the rearrangement layer  30  may extend to at least a portion of an upper surface of the semiconductor layer  10  to form an extension  31 , and it may be desirable that the photovoltaic particles  50  are positioned on the extension  31  to increase the amount of power generation. 
       FIG.  6    shows an embodiment in which the extension  31  of the rearrangement layer  30  is formed and shows that the photovoltaic particles  50  are formed on the extension  31  covering the upper surface of the semiconductor layer  10 . Furthermore,  FIG.  6    shows an embodiment of the semiconductor layer in more detail. The feature of the semiconductor layer in  FIG.  6    may all be applied to the feature of the semiconductor layer  10  of the present disclosure, but the feature of the semiconductor layer  10  of the present disclosure is not limited thereto. Referring to the semiconductor layer  10  in  FIG.  6   , pads  13  of the semiconductor chip  11  for processing information inside the semiconductor layer  10  may be electrically connected to the external terminals  40  in the power generation connection part  20  by a connection part  14 . In addition, the mold portion  12  for protecting the semiconductor chip  11 , the pads  13  of the semiconductor chip, the connection part  14 , etc. may surround a portion of the rearrangement layer  30  to bond the rearrangement layer  30  and the semiconductor layer  10  in the semiconductor package. 
     The external terminals  40  and the photovoltaic particles  50  may be formed on the other side as well as one side of the rearrangement layer  30  in order to increase the amount of power generation of the semiconductor package, so the power generation connection layer  20  may be formed on both sides of the rearrangement layer  30 . The rearrangement layer  30  may connect the photovoltaic particles by wire bonding, flip chip bonding, etc., and the method of connecting the photovoltaic particles is not particularly limited.  FIG.  7    schematically shows a structure in which the power generation connection layers  20  are formed on both sides of the rearrangement layer  30 . Referring to  FIG.  7   , the external terminals and the photovoltaic particles are formed in each of the power generation connection layers  20   a  and  20   b  respectively on both sides of the rearrangement layer  30 . Considering the direction in which light is incident, it may be desirable that the number of the photovoltaic particles distributed in the power generation connection layer  20   b  positioned above is greater than the number of the photovoltaic particles distributed in the power generation connection layer  20   a  contiguous to the substrate for more efficient photovoltaic power generation and improvement of the speed of processing information of the semiconductor package. 
     In order to increase the amount of light of the photovoltaic particles  50 , various structures of a reflection portion may be additionally introduced into the semiconductor package, and, for example, the structure of the reflection portion may be formed by printing, mechanical processing, etc. 
     For example, to increase the amount of the light of the photovoltaic particles  50 , the reflection portions may be formed around the power generation connection layer  20  on the substrate  60 , given that the area of the substrate  60  is generally larger than that of the semiconductor layer  10  in the semiconductor package. In this case, the reflection portions  90  may be formed only on a portion of the perimeter of the power generation connection layer, or may be formed on the entire perimeter.  FIGS.  8  and  9    are cross-sectional views schematically showing an embodiment in which the reflection portions are formed. When the reflection portions are formed around the power generation connection layer  20  on the substrate  60 , even light that is incident on the substrate but is not utilized as power for the semiconductor package may be reflected and transmitted to the power generation connection layer by the reflection portions so that the amount of light incident on the power generation connection layer may increase and the amount of power generation of the semiconductor package may increase. 
     The reflection portions  90  may be formed not only on the substrate but also on the rearrangement layer, and may be disposed between the external terminals  40  and the photovoltaic particles  50  in the power generation connection layer  20  so that an optical waveguide may be formed. 
     In the power generation connection layer  20 , the photovoltaic particles  50  may be positioned together with the external terminals  40  below the semiconductor chip  11  in the semiconductor layer  10 , and may be positioned below the semiconductor layer  10  but not below the semiconductor chip  11 . However, since semiconductor chips generally have very low or no light transmittance, it may be desirable that the photovoltaic particles  50  are positioned on the periphery of the power generation connection layer  20  in order to maximize the amount of photovoltaic power generation of the semiconductor package when a certain number of the photovoltaic particles  50  is used.  FIG.  10    is a bottom view showing an embodiment of the arrangement of the external terminals  40  and the photovoltaic particles  50  in the power generation connection layer  20 , and shows that the photovoltaic particles are formed on the periphery of the power generation connection layer  20 . 
     The semiconductor package may store electricity generated from the photovoltaic particles and include a battery to supply power to the semiconductor layer when light sources are insufficient, and it may be desirable that the battery is a rechargeable battery that can be charged and discharged. 
     Although the embodiments of the present disclosure have been described in detail above, the scope of the present disclosure is not limited thereto. In addition, it is to be understood by a person having ordinary skill in the technical field that various modifications and variations can be made within the scope of the technology of the present disclosure described in the appended claims.