Stacked package structure and its fabrication method

Abstract

This invention relates to a stacked packaging structure and a method for manufacturing the stacked packaging structure. The stacked packaging structure includes at least two optoelectronic chips, with multiple optoelectronic chips stacked along the thickness direction. Each optoelectronic chip includes a waveguide and an optical reflection module. The waveguide is used to conduct a preset optical signal; the optical reflection module includes a reflective surface for reflecting the optical signal, the reflective surface being inclined relative to the plane of the waveguide, and used to receive and reflect the optical signal. In this structure, the optical reflection module can not only change the transmission direction of the optical signal transmitted from the waveguide, allowing other optoelectronic chips arranged perpendicularly along the thickness direction to receive the corresponding optical signal, but also transmit the received optical signal back to its own waveguide. Through these settings, the stacked packaging structure can meet the needs of various configurations, improving the flexibility and adaptability of its overall structure.

Description

Technical Field

[0001] This invention belongs to the field of chip technology, and in particular relates to a stacked packaging structure and a method for manufacturing the stacked packaging structure. Background Technology

[0002] With the development of optoelectronic chips, their design and packaging are trending towards higher capacity, higher density, and smaller size. In recent years, coupling between different chips has been limited to flat placement and coupling via end faces. This packaging method is commonly referred to as two-dimensional packaging. However, two-dimensional packaging structures occupy a large area and lack flexibility and adaptability. Summary of the Invention

[0003] This application provides an optoelectronic chip, a stacked packaging structure, and a method for fabricating the optoelectronic chip, which can effectively utilize vertical space and improve the adaptability of the overall structure.

[0004] According to a first aspect of this application, a photoelectronic chip is provided for transmitting a preset optical signal, the photoelectronic chip comprising:

[0005] Waveguides are used to transmit preset optical signals;

[0006] An optical reflection module includes a reflective surface for reflecting optical signals, the reflective surface being inclined relative to the plane in which the waveguide is located; the optical reflection module is connected to the waveguide and is used to receive the optical signal transmitted by the waveguide and reflect the optical signal along a second direction, the second direction having a component in the thickness direction of the optoelectronic chip; or it is used to receive an optical signal emitted along the second direction and reflect the optical signal to the waveguide.

[0007] Furthermore, the optoelectronic chip includes a front side and a back side disposed opposite to each other along the thickness direction; the second direction is parallel to the thickness direction and perpendicular to the front side and the back side.

[0008] The reflective surface is a concave curved surface, and is used to convert the received light signal emitted by the waveguide into light signals perpendicular to the front and back sides of the optoelectronic chip by reflection, or to convert the received light signals perpendicular to the front and back sides of the optoelectronic chip into light signals parallel to or coincident with the plane of the waveguide and emitted towards the waveguide by reflection.

[0009] Furthermore, the optoelectronic chip includes a front side and a back side disposed opposite to each other along the thickness direction, and the front side is provided with functional pins;

[0010] The optoelectronic chip further includes an electrical connection layer that extends through the optoelectronic chip along its thickness direction; one end of the electrical connection layer extends to the front side of the chip and is electrically connected to the functional pin; the other end of the electrical connection layer extends to the back side of the chip and forms an exposed pin.

[0011] Furthermore, the minimum distance between the electrical connection layer and the light reflection module is less than or equal to 50 micrometers; and / or,

[0012] The optoelectronic chip also includes solder balls, one end of which is electrically connected to the exposed pin, and the other end is used to electrically connect to other electronic components.

[0013] Furthermore, the optoelectronic chip includes a substrate layer, and the waveguide and the optical reflection module are both disposed above the substrate layer; the substrate layer is transparent relative to the operating wavelength of the preset optical signal; and / or,

[0014] The light reflection module includes a first filling portion and a second filling portion, and a metal reflective layer is provided between the first filling portion and the second filling portion, the metal reflective layer serving as the reflective surface.

[0015] Furthermore, the optoelectronic chip may include one or two light reflection modules;

[0016] When there are two optical reflection modules, the two optical reflection modules are respectively located at opposite ends of the waveguide along the extension direction; one optical reflection module is used to receive optical signals entering from the outside and reflect the optical signals to the waveguide; the other optical reflection module is used to receive optical signals transmitted by the waveguide and reflect the optical signals to the outside.

[0017] According to a second aspect of this application, a stacked packaging structure is provided, the stacked packaging structure comprising at least two optoelectronic chips as described above, and a plurality of the optoelectronic chips being stacked and arranged along the thickness direction.

[0018] Furthermore, an interlayer connection layer is provided between two adjacent optoelectronic chips. Electrical pins are provided on the front and / or back of the optoelectronic chips. The interlayer connection layer abuts against the electrical pins of the two adjacent optoelectronic chips and is used to electrically connect the two adjacent optoelectronic chips.

[0019] Furthermore, the optoelectronic chip includes a front side and a back side disposed opposite to each other along the thickness direction;

[0020] In two adjacent optoelectronic chips, the front of the upper optoelectronic chip faces the front of the lower optoelectronic chip, and the light reflection module of the upper optoelectronic chip faces the light reflection module of the lower optoelectronic chip; or, the back of the upper optoelectronic chip faces the front of the lower optoelectronic chip, and the light reflection module of the upper optoelectronic chip faces the light reflection module of the lower optoelectronic chip.

[0021] Furthermore, the stacked packaging structure includes at least three optoelectronic chips stacked sequentially along the thickness direction; the lower optoelectronic chip among the three adjacent optoelectronic chips is designated as the first optoelectronic chip, the middle optoelectronic chip as the second optoelectronic chip, and the upper optoelectronic chip as the third optoelectronic chip.

[0022] The second optoelectronic chip includes two optical reflection modules, which are respectively located at opposite ends of the waveguide along its extension direction; one of the optical reflection modules is used to receive the optical signal emitted by the first optoelectronic chip and to reflect the optical signal to the waveguide; the other optical reflection module is used to receive the optical signal transmitted by the waveguide and to reflect the optical signal to the third optoelectronic chip.

[0023] According to a third aspect of this application, a method for fabricating an optoelectronic chip is provided, which is used to fabricate the optoelectronic chip as described above, the method for fabricating the optoelectronic chip comprising:

[0024] A substrate is provided, the substrate including a substrate layer, a cladding layer and a waveguide, the cladding layer and the waveguide being located on the substrate layer, and the cladding layer encapsulating the waveguide;

[0025] A groove is formed on the side of the cladding layer away from the substrate layer;

[0026] A first filling portion is formed in the groove, and the first filling portion exists only in a portion of the space of the groove;

[0027] A metallic reflective layer is formed on the first filling portion;

[0028] A second filling portion is formed in the remaining space of the groove.

[0029] Furthermore, the step of forming the first filling portion in the groove includes: filling the groove with a first filling material, the first filling material completely filling the groove; forming a groove surface on the surface of the first filling material by grayscale etching, thus forming the first filling portion; and / or,

[0030] The method for fabricating the optoelectronic chip further includes: drilling holes downwards on the surface of the cladding layer away from the substrate layer to form counterbore, the counterbore extending into the interior of the substrate layer; filling the counterbore with a conductive metal material to form an electrical connection layer; and grinding the surface of the substrate layer away from the cladding layer until the electrical connection layer is exposed.

[0031] The technical solutions provided by the embodiments of this disclosure may include the following beneficial effects:

[0032] In the above structure, the principle of reflecting optical signals using an optical reflection module can change the propagation direction of the optical signal transmitted from the waveguide, and give the optical signal a certain component in the thickness direction. This allows other optoelectronic chips arranged perpendicularly along the thickness direction to receive the optical signal transmitted from this optoelectronic chip. Simultaneously, the received optical signal emitted along the thickness direction can be propagated back to its own waveguide for further propagation. Through this arrangement, optical signal transmission between optoelectronic chips stacked along the thickness direction can be achieved, forming a stacked packaging structure. This structure effectively utilizes the vertical direction, allowing the stacked packaging structure to meet various form requirements and improving the overall structural flexibility and adaptability.

[0033] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and are not intended to limit the invention. Attached Figure Description

[0034] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention.

[0035] Figure 1 This is a schematic diagram of a stacked packaging structure according to an embodiment of the present invention.

[0036] Figure 2 This is a schematic diagram of another stacked packaging structure according to an embodiment of the present invention.

[0037] Figure 3 This is a schematic diagram illustrating another stacked packaging structure according to an embodiment of the present invention.

[0038] Figure 4 This is a schematic flowchart illustrating a method for fabricating an optoelectronic chip according to an embodiment of the present invention.

[0039] Figure 5 This is a fabrication process diagram of an optoelectronic chip according to an embodiment of the present invention.

[0040] Figure 6 This is a schematic diagram illustrating another fabrication process of an optoelectronic chip according to an embodiment of the present invention.

[0041] Figure 7 This is a further fabrication process diagram of an optoelectronic chip according to an embodiment of the present invention.

[0042] Figure 8 This is another fabrication process diagram of an optoelectronic chip according to an embodiment of the present invention.

[0043] Figure 9 This is another fabrication process diagram of an optoelectronic chip according to an embodiment of the present invention.

[0044] Figure 10 This is another fabrication process diagram of an optoelectronic chip according to an embodiment of the present invention.

[0045] Figure 11 This is another fabrication process diagram of an optoelectronic chip according to an embodiment of the present invention.

[0046] Figure 12 This is another fabrication process diagram of an optoelectronic chip according to an embodiment of the present invention.

[0047] Figure 13 This is a fabrication process diagram of another optoelectronic chip according to an embodiment of the present invention.

[0048] Figure 14 This is a further fabrication process diagram of another optoelectronic chip according to an embodiment of the present invention.

[0049] Figure 15 This is another fabrication process diagram of another optoelectronic chip according to an embodiment of the present invention.

[0050] Figure 16 This is a schematic diagram of the structure of a first optoelectronic chip according to an embodiment of the present invention.

[0051] Figure 17 This is a schematic diagram of the structure of a second optoelectronic chip according to an embodiment of the present invention.

[0052] Explanation of reference numerals in the attached figures

[0053] Stacked package structure 10

[0054] Optoelectronic Chip 20

[0055] Front 21

[0056] Back 22

[0057] Functional pin 23

[0058] 24 exposed pins

[0059] First Optoelectronic Chip 25

[0060] Second optoelectronic chip 26

[0061] Third optoelectronic chip 27

[0062] Waveguide 100

[0063] Light reflection module 200

[0064] Reflective surface 210

[0065] First filling section 220

[0066] First filling material 221

[0067] Surface 222

[0068] Second filling section 230

[0069] Metal reflective layer 240

[0070] Substrate 300

[0071] Countersunk Hole 310

[0072] Electrical connection layer 400

[0073] 500 solder balls

[0074] 600 coating layer

[0075] Groove 610

[0076] Interlayer connection layer 700

[0077] First direction X

[0078] Thickness direction H

[0079] Minimum distance d1 Detailed Implementation

[0080] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numerals in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present invention. Rather, they are merely examples of apparatuses and methods consistent with some aspects of the invention as detailed in the appended claims.

[0081] The terminology used in this application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. Unless otherwise defined, the technical or scientific terms used in this application should be understood in their ordinary sense by one of ordinary skill in the art to which this invention pertains. The terms "a" or "one" and similar words used in this application specification and claims do not indicate a limitation of quantity, but rather indicate the presence of at least one. "A plurality of" means two or more. The terms "comprising" or "including" and similar words mean that the elements or objects preceding "comprising" or "including" encompass the elements or objects listed following "comprising" or "including" and their equivalents, and do not exclude other elements or objects.

[0082] The terms “connection” or “linked” are not limited to physical or mechanical connections and can include electrical connections, whether direct or indirect. The terms “upper” and / or “lower” are used for ease of description only and are not intended to limit a location or spatial orientation. The singular forms “a,” “described,” and “the” used in this specification and appended claims are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the term “and / or” as used herein refers to and includes any or all possible combinations of one or more of the associated listed items.

[0083] like Figure 1 , Figure 2 and Figure 3 As shown, this application discloses a stacked package structure 10. The stacked package structure 10 includes a plurality of optoelectronic chips 20. The plurality of optoelectronic chips 20 are stacked and arranged along the thickness direction H. The optoelectronic chips 20 include a front side 21 and a back side 22 disposed opposite to each other along the thickness direction H. The stacked package structure 10 can be used not only to conduct and process optical signals, but also to process or store electrical signals. Specifically, the stacked structure may include two optoelectronic chips 20 (see reference). Figure 1 and Figure 2 As shown), it can also include three optoelectronic chips 20 (see reference). Figure 3 As shown), it can also include four or more optoelectronic chips 20.

[0084] In two adjacent optoelectronic chips 20, the back surface 22 of the upper optoelectronic chip 20 can face the front surface 21 of the lower optoelectronic chip 20 (reference). Figure 1 (As shown), the front surface 21 of the upper photoelectronic chip 20 can also face the front surface 21 of the lower photoelectronic chip 20 (see reference). Figure 2(As shown). It should be noted that "front side 21" refers to the surface of the optoelectronic chip 20 where the functional areas are located. In other words, the functional pins 23 of the optoelectronic chip 20 used for conducting electrical signals are located on the front side 21. "Back side 22" refers to the surface opposite to the front side 21.

[0085] The optoelectronic chip 20 is used to conduct a preset optical signal. It includes a waveguide 100, a cladding layer 600, an optical reflection module 200, and a substrate layer 300. The cladding layer 600 covers the waveguide 100 to protect it. The cladding layer 600, the waveguide 100, and the optical reflection module 200 are all disposed on top of the substrate layer 300.

[0086] The waveguide 100 is located in a plane parallel to the front surface of the optoelectronic chip 20 and is used to conduct a preset optical signal. Figure 1 In the diagram, for ease of illustration, waveguide 100 extends along the first direction X. However, in actual design, waveguide 100 can be curved parallel to the surface of optoelectronic chip 20. The optical reflection module 200 includes a reflective surface 210 for reflecting optical signals, which is inclined relative to the plane of waveguide 100. It is connected to waveguide 100 and receives the optical signal transmitted by waveguide 100, changing the transmission direction of the optical signal so that the optical signal is reflected along a second direction. This second direction has a component in the thickness direction H of optoelectronic chip 20, allowing the light reflected by reflective surface 210 to transmit optical signals along the thickness direction H of other stacked optoelectronic chips 20. Reflective surface 210 can also receive optical signals emitted along the second direction and reflect them back to waveguide 100. In two adjacent optoelectronic chips 20, it is necessary to ensure that the optical reflection module 200 of the upper optoelectronic chip 20 faces the optical reflection module 200 of the lower optoelectronic chip 20. Simultaneously, the substrate layer 300 is transparent relative to the preset operating wavelength of the optical signal. For example, assuming the preset optical signal is an infrared optical signal, the substrate 300 can allow the infrared optical signal to pass through. In other words, the substrate 300 is transparent relative to the wavelength of the infrared optical signal.

[0087] In the above structure, the optical reflection module 200 reflects the optical signal, changing the propagation direction of the optical signal transmitted from the waveguide 100 and ensuring that the optical signal has a certain component in the thickness direction H. This allows other optoelectronic chips 20 arranged perpendicularly along the thickness direction H to receive the optical signal transmitted from them. Simultaneously, the received optical signal emitted along the thickness direction H can be propagated back to its own waveguide 100 for further propagation. Through this configuration, optical signal transmission between the optoelectronic chips 20 stacked along the thickness direction H can be achieved, forming a stacked package structure 10. This structure effectively utilizes the vertical direction, allowing the number and position of the stacked optoelectronic chips 20 to be adjusted according to the customer's actual requirements for the size and shape of the stacked package structure 10, thus meeting various morphological needs and improving the overall structural flexibility and adaptability.

[0088] Furthermore, the reflective surface 210 is a concave curved surface, used to convert the received light signal emitted from the waveguide 100 into a light signal perpendicular to the front surface 21 and back surface 22 of the optoelectronic chip 20 through reflection. At this time, the second direction is parallel to the thickness direction H, i.e., perpendicular to the front surface 21 and back surface 22. This configuration allows the reflected light to be emitted outward perpendicular to the surface of the optoelectronic chip 20, thus avoiding light signal loss due to refraction. Simultaneously, this configuration also allows the optoelectronic chip 20 to convert the received light signal perpendicular to the front surface 21 and back surface 22 of the optoelectronic chip 20 into a light signal incident on the waveguide 100 that is parallel to or coincides with the plane where the waveguide 100 is located. It should be noted that this light signal is convergent. In the above structure, by controlling the angle of the second direction, unnecessary losses in the light signal transmission process are minimized or avoided as much as possible. It should be noted that the inventors can adjust the angle of the second direction by changing the surface morphology of the reflective surface 210 according to actual conditions, which requires extensive simulation experiments.

[0089] like Figure 1As shown, the light reflection module 200 is located on top of the optoelectronic chip 20, and the end face of the light reflection module 200 along the thickness direction H serves as at least a portion of the front side 21 or the back side 22 of the optoelectronic chip 20. It should be noted that when the optoelectronic chip 20 is placed upright, the front side 21 of the optoelectronic chip 20 is located above the back side 22. In this case, the upper part of the optoelectronic chip 20 is one side of the front side 21, and the end face of the light reflection module 200 along the thickness direction H serves as at least a portion of the front side 21 of the optoelectronic chip 20. When the optoelectronic chip 20 is placed in reverse, the optoelectronic chip 20 is located above the front side 21 of the back side 22. In this case, the upper part of the optoelectronic chip 20 is one side of the back side 22, and the end face of the light reflection module 200 along the thickness direction H serves as at least a portion of the back side 22 of the optoelectronic chip 20.

[0090] Through the above configuration, the optical signal reflected from the optical reflection module 200 in the optoelectronic chip 20 can directly move away from the optoelectronic chip 20 and enter the next optoelectronic chip 20. Alternatively, the optical signal reflected from other optoelectronic chips 20 can be directly received by the optical reflection module 200 in the optoelectronic chip 20 and reflected into its own waveguide 100 for transmission, thereby minimizing or avoiding unnecessary loss of optical signal during transmission.

[0091] like Figure 1 As shown, the light reflection module 200 includes a first filling portion 220 and a second filling portion 230. A metal reflective layer 240 is disposed between the first filling portion 220 and the second filling portion 230, serving as a reflective surface 210. Both the first filling portion 220 and the second filling portion 230 are made of transparent material to facilitate the smooth transmission of light signals between them. Simultaneously, the first filling portion 220 provides a shape base for the reflective surface 210. A metal material is coated and formed on the outside of the first filling portion 220 to form the metal reflective layer 240. The second filling portion 230 can fill recessed locations to ensure structural stability.

[0092] The optoelectronic chip 20 may include one or two light-reflecting modules 200. (Reference) Figure 3As shown, when the stacked package structure 10 contains at least three optoelectronic chips 20 stacked sequentially along the thickness direction H, the lower optoelectronic chip 20 among the three adjacent optoelectronic chips 20 is designated as the first optoelectronic chip 25, the middle optoelectronic chip 20 as the second optoelectronic chip 26, and the upper optoelectronic chip 20 as the third optoelectronic chip 27. The second optoelectronic chip 26 needs to be equipped with two optical reflection modules 200. At this time, the two optical reflection modules 200 are respectively located at opposite ends of the waveguide 100 along the extension direction. One of the optical reflection modules 200 is used to receive the optical signal entering from the outside and reflect the optical signal to the waveguide 100 in the optoelectronic chip 20. When external light enters the stacked package structure 10 from the waveguide of the first optoelectronic chip 25, the "outside" here can also be understood as the first optoelectronic chip 25, and the direction of the incident optical signal needs to be considered. In other words, the optical reflection module 200 can also be used to receive or emit optical signals from the first optoelectronic chip 25. Another optical reflection module 200 is used to receive the optical signal transmitted by the waveguide 100 in the optoelectronic chip 20 and reflect the optical signal to the outside. The "outside" here can also be understood as the third optoelectronic chip 27; in other words, the optical reflection module 200 can also be used to reflect the optical signal to the third optoelectronic chip 27. When external light enters the stacked package structure 10 from the waveguide of the third optoelectronic chip 27, the direction of optical signal transmission is reversed, and the optoelectronic chip 20 referred to as the "outside" above needs to be adjusted accordingly. Through the above settings, when multiple optoelectronic chips 20 are stacked along the thickness direction H, optical signal propagation between multiple optoelectronic chips 20 can be achieved. It should be noted that when the stacked package structure 10 contains at least four optoelectronic chips 20 arranged sequentially along the thickness direction H, the stacked package structure 10 contains at least two combinations of first optoelectronic chips 25, second optoelectronic chips 26, and third optoelectronic chips 27. In other words, the optoelectronic chip 20 located in the middle can serve as both the first optoelectronic chip 25 and the third optoelectronic chip 27, depending on the actual situation. (Reference) Figure 1As shown, when the stacked package structure 10 contains only two optoelectronic chips 20 arranged along the thickness direction H, each optoelectronic chip 20 may have only one light reflection module 200. One of the two optoelectronic chips 20 may serve as the first optoelectronic chip 25, and the other may serve as the third optoelectronic chip 27. External light enters through the first optoelectronic chip 25, and the light reflection structure in the first optoelectronic chip 25 is used to receive the light signal transmitted from the waveguide 100 in the first optoelectronic chip 25, and reflect the light signal upward along the thickness direction H to the third optoelectronic chip 27. The light reflection structure in the third optoelectronic chip 27 is used to receive the light signal emitted from the third optoelectronic chip 27 from bottom to top, and reflect the light signal into the waveguide 100 of the third optoelectronic chip 27 for propagation. Of course, light may also enter from the third optoelectronic chip 27 and be reflected by the light reflection structure into the first optoelectronic chip 25.

[0093] The aforementioned light reflection module 200 enables optical signal transmission between multiple optoelectronic chips 20 stacked along the thickness direction H. Simultaneously, to ensure effective electrical signal transmission between the optoelectronic chips 20 within the stacked package structure 10, the inventors implemented the following design:

[0094] As shown above, the functional pins 23 of the optoelectronic chip 20 are located on the front side 21 of the optoelectronic chip 20. However, when multiple optoelectronic chips 20 are stacked, in two adjacent optoelectronic chips 20, when the front side 21 of the upper optoelectronic chip 20 faces the front side 21 of the lower optoelectronic chip 20, electrical signals can be directly transmitted through the functional pins 23 of both (see reference). Figure 2 (As shown). However, when the front side 21 of the upper optoelectronic chip 20 faces the back side 22 of the lower optoelectronic chip 20, the functional pins 23 of the two are far apart, and electrical connection cannot be achieved (see reference). Figure 1 (As shown). At this point, the electrical connection layer 400 is required. At the same time, regardless of the stacking method of the optoelectronic chips 20, the electrical connection layer 400 can be used to bring out the functional pins 23 on the front side 21 to other surfaces, which is convenient for electrical connection with other optoelectronic chips 20 or other electrical devices.

[0095] For details, please refer to Figure 1As shown, the electrical connection layer 400 extends through the optoelectronic chip 20 along the thickness direction H. One end of the layer extends to the front side 21 of the chip and is electrically connected to the functional pin 23. The other end of the electrical connection layer 400 extends to the back side 22 of the chip and forms an exposed pin 24. The optoelectronic chip 20 also includes a plurality of solder balls 500, at least some of which have one end electrically connected to the exposed pin 24 and the other end used for electrical connection to other electronic components. With the above arrangement, the functional pin 23 can be led to the back side 22, facilitating the conduction of electrical signals between multiple optoelectronic chips 20.

[0096] The exposed pins 24 and functional pins 23 mentioned above can be collectively referred to as electrical pins. By forming an electrical connection layer 400 on the optoelectronic chip 20, electrical pins are provided on both the front side 21 and the back side 22 of the optoelectronic chip 20.

[0097] An interlayer connection layer 700 is disposed between two adjacent optoelectronic chips 20. The interlayer connection layer 700 abuts against the electrical pins of the two adjacent optoelectronic chips 20 and is used for electrically connecting the two adjacent optoelectronic chips 20. For example, refer to... Figure 1 As shown, when the back surface 22 of the upper optoelectronic chip 20 faces the front surface 21 of the lower optoelectronic chip 20, the interlayer connection layer 700 is electrically connected to the exposed pins 24 of the back surface 22 of the upper optoelectronic chip 20 and electrically connected to the functional pins 23 of the front surface 21 of the lower optoelectronic chip 20, thereby realizing the electrical connection between the two optoelectronic chips 20. (Reference) Figure 2 As shown, when the front side 21 of the upper optoelectronic chip 20 faces the front side 21 of the lower optoelectronic chip 20, the interlayer connection layer 700 is electrically connected to the functional pins 23 on the back side 22 of both the upper and lower optoelectronic chips 20 to achieve electrical connection between the two optoelectronic chips 20. It should be noted that the interlayer connection layer 700 can also be composed of solder balls 500.

[0098] like Figure 4 As shown, since the material of the electrical connection layer 400 is usually metal, in order to avoid the metal affecting the light signals received or reflected by the light reflection film group, it is necessary to control the minimum distance d1 between the electrical connection layer 400 and the light reflection module 200. Through numerous experiments, the inventors discovered that when the minimum distance d1 between the electrical connection layer 400 and the light reflection module 200 is less than or equal to 50 micrometers, the influence of the metal on the light signals transmitted in the optoelectronic chip 20 can be avoided.

[0099] like Figure 4 As shown, this application also discloses a method for fabricating a stacked packaging structure. This method is used to fabricate the optoelectronic chip 20 as described above, and includes the following steps:

[0100] Step 1000: Provide substrate layer 300.

[0101] Step 2000: Fabricate a cladding layer 600 and a waveguide 100 on the substrate layer 300, with the cladding layer 600 enclosing the waveguide 100. It should be noted that in other embodiments, a semi-finished substrate can be directly purchased. This substrate includes a substrate layer 300, a cladding layer 600, and a waveguide 100, with the cladding layer 600 and waveguide 100 located above the substrate layer, and the cladding layer 600 enclosing the waveguide 100. In this case, steps 1000 and 2000 are no longer necessary; only the substrate itself needs to be provided.

[0102] Step 3000: A countersunk hole 310 is formed by drilling a hole downwards on the surface of the cladding layer 600 away from the substrate layer 300, extending the countersunk hole 310 into the interior of the substrate layer 300. At this time, the overall structure is as follows: Figure 5 As shown.

[0103] Step 4000: Fill the countersunk hole 310 with a conductive metallic material to form an electrical connection layer 400. At this point, the overall structure is as follows: Figure 6 As shown.

[0104] Step 5000: Grind the surface of the substrate 300 away from the cladding layer 600 until the electrical interconnect layer 400 is exposed. At this point, the overall structure is as follows: Figure 7 As shown.

[0105] Step 6000: A groove 610 is formed on the side of the overlay layer 600 away from the substrate layer 300. At this time, the overall structure is as follows: Figure 8 As shown.

[0106] Step 7000: A first filling portion 220 is formed in the groove 610, the first filling portion 220 existing only in a portion of the space of the groove 610. At this time, the overall structure is as follows: Figure 10 and Figure 13 As shown.

[0107] Step 8000: A metallic reflective layer 240 is formed on the first filling portion 220. At this time, the overall structure is as follows: Figure 11 and Figure 14 As shown.

[0108] Step 9000: A second filling portion 230 is formed in the remaining spaces of the groove 610. At this point, the overall structure is as follows: Figure 12 and Figure 15 As shown.

[0109] With the above settings, a light reflection module 200 can be formed on the optoelectronic chip 20.

[0110] It should be noted that steps 3000 to 6000 can be executed in the aforementioned positions, or they can be executed after step 9000. It should also be noted that not all optoelectronic chips 20 require execution of steps 3000 to 6000. For example, located at... Figure 2 The optoelectronic chip on the upper middle side does not need to perform the above steps.

[0111] Specifically, step 7000: the step of forming the first filling portion 220 in the groove 610 specifically includes:

[0112] Step 7100: Fill the groove 610 with the first filler material 221 until the groove 610 is completely filled. At this point, the overall structure is as follows: Figure 9 As shown.

[0113] Step 7200: A groove surface 222 is formed on the surface of the first filling material 221 by grayscale etching, thus forming the first filling portion 220. At this time, the overall structure is as follows: Figure 10 and Figure 13 As shown.

[0114] The above configuration provides a support surface for coating the metal reflective layer 240. At the same time, by forming a recessed groove 222, the specific shape of the metal reflective layer 240 located thereon can be controlled, thereby controlling the surface shape of the reflective surface 210.

[0115] It should be noted that, regarding the above steps, steps 1000 to 7100 are identical in their fabrication methods for the first optoelectronic chip 25 and the third optoelectronic chip 27. After step 7100 is completed, the overall structure is as follows: Figure 9 As shown in the attached diagram. Steps 7100 to 9000 are implemented differently. See the attached diagram for details.

[0116] Regarding the first optoelectronic chip 25:

[0117] In step 4200, the first filling portion 220 is formed at the end of the groove 610 away from the waveguide 100. At this time, the overall structure is as follows: Figure 10 As shown.

[0118] In step 5000, a metal reflective layer 240 is formed on the first filling portion 220. At this time, the overall structure is as follows: Figure 11 As shown.

[0119] In step 6000, the second filling portion 230 is formed at one end of the waveguide 100 near the groove 610. At this time, the overall structure is as follows: Figure 12 As shown.

[0120] Regarding the third optoelectronic chip 27:

[0121] In step 4200, the first filling portion 220 is formed at the end of the groove 610 near the waveguide 100. At this time, the overall structure is as follows: Figure 13 As shown.

[0122] In step 5000, a metal reflective layer 240 is formed on the first filling portion 220. At this time, the overall structure is as follows: Figure 14 As shown.

[0123] In step 6000, the second filling portion 230 is formed at the end of the groove 610 away from the waveguide 100. At this time, the overall structure is as follows: Figure 15 As shown.

[0124] It should be noted that the formation process of exposed pin 24 and functional pin 23 is relatively conventional, and therefore is not shown in the above steps.

[0125] After performing the above steps, the first optoelectronic chip 25 exhibits the following characteristics: Figure 16 The structure shown indicates that the second optoelectronic chip 26 exhibits the following characteristics: Figure 17 The structure shown. Then, the two are electrically connected via an interlayer connection layer 700 to achieve the desired structure. Figure 1 The stacked packaging structure 10 shown.

[0126] In this application, the structural embodiments and method embodiments described can complement each other without conflict.

[0127] In this invention, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance. The terms "multiple" and "several" refer to two or more unless otherwise expressly defined.

[0128] Other embodiments of the invention will readily occur to those skilled in the art upon consideration of the disclosure in this specification. This invention is intended to cover any variations, uses, or adaptations of the invention that follow the general principles of the invention and include common knowledge or customary techniques in the art not disclosed herein. The specification and examples are to be considered exemplary only, and the true scope and spirit of the invention are indicated by the following claims.

[0129] It should be understood that the present invention is not limited to the precise structure described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of the invention is limited only by the appended claims.

Claims

1. A stacked package structure, comprising at least two optoelectronic chips, a plurality of the optoelectronic chips being arranged in a stack along a thickness direction; the optoelectronic chips being configured to conduct a preset optical signal, characterized in that: the optoelectronic chip comprises: a waveguide configured to conduct the preset optical signal; a cladding layer wrapping the waveguide; a groove formed on the cladding layer; and a light reflection module fixed in the groove and adhering to a side wall of the groove, the light reflection module comprising a first filling portion, a second filling portion and a metal reflection layer, the metal reflection layer being sandwiched between the first filling portion and the second filling portion, the metal reflection layer comprising a reflection surface configured to reflect the optical signal, the reflection surface being arranged obliquely relative to a plane in which the waveguide is located, one of the first filling portion and the second filling portion adhering to the side wall of the groove and adhering to the waveguide, and the other of the first filling portion and the second filling portion adhering to the side wall of the groove and being away from the waveguide, a surface of the first filling portion and the second filling portion adhering to the metal reflection layer being in a convex or concave arc structure; wherein the light reflection module in one optoelectronic chip is connected with the waveguide and configured to receive the optical signal conducted by the waveguide and reflect the optical signal to a next optoelectronic chip along a second direction, the second direction having a component in the thickness direction of the optoelectronic chip; the light reflection module in the next optoelectronic chip is configured to receive the optical signal emitted by the previous optoelectronic chip along the second direction and reflect the optical signal to the waveguide; in the stacked package structure, the reflection surfaces of the two light reflection modules facing each other in the two adjacent optoelectronic chips along the second direction have opposite oblique angles; the optoelectronic chip further comprises a solder ball, two ends of the solder ball being electrically connected to pins of adjacent optoelectronic chips, respectively; the two adjacent optoelectronic chips are arranged with a spacing, and the light reflection module is not filled. The optoelectronic chip comprises a front surface and a back surface arranged oppositely along the thickness direction; the second direction is parallel to the thickness direction and perpendicular to the front surface and the back surface; the reflection surface is a concave curved surface and is configured to convert the received optical signal emitted by the waveguide into optical signal perpendicular to the front surface and the back surface of the optoelectronic chip by reflection, or configured to convert the received optical signal perpendicular to the front surface and the back surface of the optoelectronic chip into optical signal parallel or coinciding with a plane in which the waveguide is located and incident to the waveguide by reflection. The optoelectronic chip comprises a front surface and a back surface arranged oppositely along the thickness direction, and the front surface is provided with functional pins; the optoelectronic chip further comprises an electrical connection layer, the electrical connection layer penetrating the optoelectronic chip along the thickness direction, one end of the electrical connection layer extending to the front surface of the chip and being electrically connected to the functional pins, and the other end of the electrical connection layer extending to the back surface of the chip and forming an exposed pin; the minimum distance between the electrical connection layer and the light reflection module is less than or equal to 50 microns. ​ ​ ​ ​ ​ ​ 2. The stacked package structure of claim 1, wherein, ​ ​ 3. The stacked package structure of claim 1, wherein, ​ ​ 4. The stacked package structure of claim 3, wherein, ​ 5. The stacked package structure of claim 1, wherein, The optoelectronic chip comprises a substrate layer, and the waveguide and the optical reflection module are arranged above the substrate layer; the substrate layer is transparent to a working waveband of the preset optical signal.

6. The stacked package structure of claim 1, wherein, The optoelectronic chip can comprise one or two optical reflection modules. When the number of the optical reflection modules is two, the two optical reflection modules are respectively arranged at two ends of the waveguide opposite to each other in the extending direction; one of the optical reflection modules is used for receiving an optical signal entering from outside and reflecting the optical signal to the waveguide; and the other optical reflection module is used for receiving an optical signal conducted by the waveguide and reflecting the optical signal to outside.

7. The stacked package structure of claim 1, wherein, An interlayer connecting layer is arranged between two adjacent optoelectronic chips, and the front surface and / or the back surface of the optoelectronic chip is provided with an electrical pin; the interlayer connecting layer abuts against the electrical pin of the two adjacent optoelectronic chips and is used for electrically connecting the two adjacent optoelectronic chips.

8. The stacked package structure of claim 1, wherein, The optoelectronic chip comprises a front surface and a back surface opposite to each other in the thickness direction. In the two adjacent optoelectronic chips, the front surface of the upper optoelectronic chip faces the front surface of the lower optoelectronic chip, and the optical reflection module of the upper optoelectronic chip faces the optical reflection module of the lower optoelectronic chip; or the back surface of the upper optoelectronic chip faces the front surface of the lower optoelectronic chip, and the optical reflection module of the upper optoelectronic chip faces the optical reflection module of the lower optoelectronic chip.

9. The stacked package structure of claim 1, wherein, The stacked package structure comprises at least three optoelectronic chips stacked and arranged in sequence in the thickness direction; the lower optoelectronic chip among the three adjacent optoelectronic chips is taken as a first optoelectronic chip, the middle optoelectronic chip is taken as a second optoelectronic chip, and the upper optoelectronic chip is taken as a third optoelectronic chip. The second optoelectronic chip comprises two optical reflection modules, and the two optical reflection modules are respectively arranged at two ends of the waveguide opposite to each other in the extending direction; one of the optical reflection modules is used for receiving an optical signal emitted by the first optoelectronic chip and reflecting the optical signal to the waveguide; and the other optical reflection module is used for receiving an optical signal conducted by the waveguide and reflecting the optical signal to the third optoelectronic chip.

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