Interposer, photoelectric co-packaging structure and preparation method thereof

Abstract

The invention discloses an interposer, a photoelectric co-packaging structure and a preparation method thereof, and the interposer comprises a substrate which comprises a glass substrate or a quartz substrate; the first waveguide layer is arranged on the substrate, and at least one first waveguide structure is arranged in the first waveguide layer; the first waveguide structure comprises a first optical waveguide; the second waveguide layer is arranged on the side, away from the substrate, of the first waveguide layer, and at least one second waveguide structure is arranged in the second waveguide layer; the second waveguide structure comprises N second optical waveguides, third optical waveguides,... and (N + 1) th optical waveguides which are sequentially stacked on one side, far away from the substrate, of the first waveguide layer; wherein 1 < = N; the refractive indexes of the second optical waveguide, the third optical waveguide,..., and the N + 1th optical waveguide are sequentially increased, and the refractive index of the second optical waveguide is greater than the refractive index of the first optical waveguide. The technical scheme of the invention aims to provide the photoelectric co-packaging structure capable of realizing high-density integration.

Description

Technical Field

[0001] The present application belongs to the field of optoelectronic co-packaging technology, and in particular, relates to an intermediate layer, an optoelectronic co-packaging structure and a preparation method thereof. Background Art

[0002] At present, the optoelectronic co-packaging structure provided in the related art includes a chip, an intermediate layer of glass material, and an optical waveguide of glass material, wherein an optical waveguide is arranged inside the chip, and an optical waveguide of glass material is arranged inside the intermediate layer of glass material. In addition, the refractive index contrast of the glass optical waveguide is low, which leads to a weaker binding ability of the optical waveguide to the light field, making the bending radius of the optical waveguide larger, further leading to an increase in the size of the optical waveguide, thereby causing the intermediate layer of glass material to have a limited integration density when realizing optical interconnection.

[0003] In addition, compared with the mode fields of optical waveguides made of other materials, the mode field distribution of the optical waveguide made of glass material is relatively divergent, which is not conducive to efficient coupling with waveguides made of other materials. In addition, the coupling length of the optical waveguide made of glass material is relatively long during the coupling process. Therefore, the number of optical waveguides packaged on the glass interposer is limited, resulting in the inability to achieve higher density integration in the optoelectronic co-packaging structure in the related technology.

[0004] Therefore, there is an urgent need for an optoelectronic co-packaging structure that can achieve high-density integration. Summary of the invention

[0005] The present application provides an intermediate layer, an optoelectronic co-packaging structure and a preparation method thereof, aiming to provide an optoelectronic co-packaging structure capable of achieving high-density integration.

[0006] In a first aspect, the present application provides an intermediary layer, including:

[0007] A substrate, wherein the substrate comprises a glass substrate or a quartz substrate;

[0008] A first waveguide layer, wherein the first waveguide layer is disposed on the substrate, and at least one first waveguide structure is disposed in the first waveguide layer; the first waveguide structure comprises a first optical waveguide;

[0009] a second waveguide layer, wherein the second waveguide layer is arranged on a side of the first waveguide layer away from the substrate, and at least one second waveguide structure is arranged in the second waveguide layer; the second waveguide structure comprises N second optical waveguides, a third optical waveguide, ..., an N+1th optical waveguide, which are sequentially stacked and arranged on a side of the first waveguide layer away from the substrate; wherein 1≤N;

[0010] The refractive indexes of the second optical waveguide, the third optical waveguide, ..., and the N+1th optical waveguide increase in sequence, and the refractive index of the second optical waveguide is greater than the refractive index of the first optical waveguide.

[0011] In some embodiments, the first optical waveguide and the second optical waveguide are coupled to form a coupling structure.

[0012] In some embodiments, the first waveguide structure further includes: a first optical coupler, the first optical coupler being disposed on a side of the first optical waveguide close to and / or away from the substrate;

[0013] and / or,

[0014] The second waveguide structure further includes: a second optical coupler, the second optical coupler being arranged on a side of the second optical waveguide close to and / or away from the first optical waveguide;

[0015] Also includes:

[0016] The optical element is configured to cooperate with the first waveguide structure and / or the second waveguide structure to transmit light.

[0017] In some embodiments, a material of the first optical waveguide includes at least one of glass, silicon dioxide, and silicon oxynitride.

[0018] In some embodiments, the first optical waveguide comprises:

[0019] a first cladding layer, the first cladding layer being disposed on the substrate;

[0020] A first core layer, the first core layer is arranged on a side of the first cladding layer away from the substrate;

[0021] a first protective layer, the first protective layer being arranged on a side of the first core layer away from the first cladding layer;

[0022] and / or,

[0023] The second optical waveguide comprises:

[0024] a second cladding layer, the second cladding layer being disposed on the first protective layer;

[0025] a second core layer, the second core layer being arranged on a side of the second cladding layer away from the first protective layer;

[0026] A second protective layer is provided on a side of the second core layer away from the second cladding layer.

[0027] In some embodiments, the intermediary layer further includes:

[0028] at least one through hole, the through hole penetrating the interposer;

[0029] The orthographic projection of the through hole on the substrate does not overlap with the orthographic projections of the first waveguide structure and the second waveguide structure on the substrate.

[0030] In some embodiments, the through hole includes a first through hole and a second through hole that are interconnected;

[0031] The orthographic projection of the first through hole on the substrate covers the orthographic projection of the second through hole on the substrate.

[0032] In some embodiments, the intermediary layer further includes:

[0033] An electrode is disposed in the second waveguide layer, and an orthographic projection of the electrode on the substrate partially overlaps with an orthographic projection of the second waveguide structure on the substrate.

[0034] The interposer provided in the present application can be applied to a chip packaging structure, and the interposer is provided by firstly providing a first waveguide layer on a glass substrate, and then providing a second waveguide layer on the first waveguide layer, and a second waveguide structure is provided in the second waveguide layer, and the second waveguide structure includes N second optical waveguides, third optical waveguides, ..., N+1 optical waveguides which are sequentially stacked and arranged on the side of the first waveguide layer away from the substrate, and the refractive indexes of the second optical waveguide, the third optical waveguide, ..., and the N+1 optical waveguide are sequentially increased and are greater than the refractive indexes of the glass substrate and the first waveguide of the glass material. In this arrangement, the glass substrate can be used for connecting an optical signal with an external medium such as an optical fiber, and the second optical waveguides, the third optical waveguides, ..., and the N+1 optical waveguides which are sequentially stacked and arranged on the side of the first waveguide layer away from the substrate in the high-refractive-index second waveguide structure can be used for efficient interconnection with a chip (e.g., a photonic integrated circuit (PICs) chip) provided on the interposer.

[0035] Compared with the optical waveguide made of glass material in the related art, the optical waveguide (second optical waveguide, third optical waveguide, ..., N+1th optical waveguide) stacked and arranged on the side of the first waveguide layer away from the substrate provided by the present application has a refractive index greater than the refractive index of glass, and the arrangement mode in which the refractive index increases successively not only solves the problem of low integration of the interposer and chip packaging structure caused by the large bending radius of the glass optical waveguide in the related art and the large routing size of the optical waveguide, but also solves the problem of long coupling length and large coupling loss caused by the mode field difference between the optical waveguide in the interposer and the optical waveguide in the chip, thereby realizing higher density integration of the chip packaging structure and efficient optical signal transmission modulation.

[0036] On the other hand, the present application also provides an optoelectronic co-packaging structure, comprising:

[0037] At least one chip, RDL lines, and the interposer described in the above embodiments;

[0038] The chip is arranged in a first through hole of the interposer, the RDL line is arranged in a second through hole of the interposer, and one end of the RDL line is electrically connected to the chip through the first through hole, and the other end is electrically connected to the circuit board through the second through hole.

[0039] On the other hand, the present application also provides a method for preparing an optoelectronic co-packaging structure, the preparation method comprising:

[0040] Forming a first waveguide layer on a glass substrate or a quartz substrate, etching at least one first waveguide structure on the first waveguide layer by a dry etching process, and forming the first waveguide layer; the first waveguide structure includes a first optical waveguide;

[0041] A second waveguide layer is formed on the first waveguide layer, and at least one second waveguide structure is etched on the second waveguide layer by a dry etching process to form the second waveguide layer; the second waveguide structure comprises N second optical waveguides, third optical waveguides, ..., N+1 optical waveguides which are sequentially stacked and arranged on a side of the first waveguide layer away from the substrate; wherein 1≤N; the refractive indexes of the second optical waveguides, the third optical waveguides, ..., N+1 optical waveguides are increased sequentially, and the refractive index of the second optical waveguide is greater than the refractive index of the first optical waveguide;

[0042] Depositing electrodes in the second waveguide layer, and etching on the second waveguide layer, penetrating the second waveguide layer to the substrate, to form a through hole; wherein the through hole comprises a first through hole and a second through hole interconnected with each other; and the orthographic projection of the first through hole on the substrate covers the orthographic projection of the second through hole on the substrate;

[0043] A chip and an RDL line are respectively arranged in the first through hole and the second through hole, and one end of the RDL line is electrically connected to the chip through the first through hole, and the other end of the RDL line is electrically connected to the circuit board through the second through hole. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] The above and / or additional aspects and advantages of the present application will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0045] Figure 1A A partial structural schematic diagram of an optoelectronic co-packaging structure provided for related technology.

[0046] Figure 1B for Figure 1A A schematic diagram comparing the size of the mode field of the glass optical waveguide in the optoelectronic co-packaging structure and the optical waveguide in the chip is provided.

[0047] Figure 1A schematic diagram of the structure of an intermediary layer provided in an embodiment of the present application.

[0048] Figure 2 A schematic structural diagram of an optoelectronic co-packaging structure provided in an embodiment of the present application.

[0049] Figure 3 A schematic diagram of a coupling structure provided in an embodiment of the present application.

[0050] Figure 4 A schematic diagram of a transmission path of an optical signal in an interposer provided in an embodiment of the present application.

[0051] Figure 5 A schematic diagram of a transmission path of an optical signal in a chip co-packaging structure provided in an embodiment of the present application.

[0052] Figure 6 A schematic flow chart of a method for preparing an optoelectronic co-packaging structure provided in an embodiment of the present application.

[0053] Figure 7 A schematic diagram of the process of a method for preparing an optoelectronic co-packaging structure provided in an embodiment of the present application. DETAILED DESCRIPTION

[0054] The following will be combined with the accompanying drawings to clearly and completely describe the technical solutions in some embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments provided by the present application, all other embodiments obtained by ordinary technicians in this field belong to the scope of protection of the present application.

[0055] Unless the context requires otherwise, throughout the specification and claims, the term "comprising" is to be construed in an open, inclusive sense, ie, meaning "including, but not limited to."

[0056] In the following, the terms "first" and "second" are used for descriptive purposes only and are not to be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the embodiments of the present application, unless otherwise specified, "plurality" means two or more.

[0057] When describing some embodiments, the term "connection" and its derivative expressions may be used. The term "connection" should be understood in a broad sense. For example, "connection" can be a fixed connection, a detachable connection, or an integral connection; it can be directly connected or indirectly connected through an intermediate medium. For example, when describing some embodiments, the term "connection" may be used to indicate that two or more components are in direct physical or electrical contact with each other.

[0058] Additionally, the use of “based on” is meant to be open and inclusive, as a process, step, calculation, or other action “based on” one or more stated conditions or values ​​may, in practice, be based on additional conditions or values ​​beyond those stated.

[0059] It will be understood that when a layer or an element is referred to as being on another layer or substrate, it can be directly on the other layer or substrate, or intervening layers may be present between the layer or element and the other layer or substrate.

[0060] Exemplary embodiments are described herein with reference to cross-sectional views that are idealized exemplary drawings. In the drawings, the thickness of layers and the area of ​​regions are exaggerated for clarity. Therefore, variations in shape relative to the drawings due to, for example, manufacturing techniques and / or tolerances are conceivable. Therefore, the exemplary embodiments should not be interpreted as being limited to the shapes of the regions shown herein, but include deviations in shape due to, for example, manufacturing. Therefore, the regions shown in the drawings are schematic in nature, and their shapes are not intended to illustrate the actual shape of regions of the device, and are not intended to limit the scope of the exemplary embodiments.

[0061] Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present application, and cannot be understood as limiting the present application.

[0062] With the booming development of artificial intelligence (AI), 5G communications, the Internet of Things (IoT) and big data technologies, global data traffic has increased dramatically, driving the demand for higher bandwidth and lower latency transmission. Existing data centers and high-performance computing systems usually rely on traditional pluggable optical modules for optical-to-electrical conversion, but this solution faces significant technical bottlenecks.

[0063] For example, pluggable optical modules are usually connected to ASIC chips via copper wires. Due to the long transmission distance of copper wires, signal insertion loss increases, especially at high-speed transmission, signal integrity and transmission efficiency decrease significantly. In this case, signal loss not only increases the energy consumption of the system, but also limits the data transmission rate. In addition, as the scale of the system expands, the physical space occupied by pluggable optical modules is large, which makes it difficult to meet the requirements of high-density packaging, further exacerbating the complexity and signal loss in the transmission path.

[0064] At this time, as an emerging optoelectronic integration technology, co-packaged optics (CPO) significantly shortens the transmission distance of optoelectronic signals by tightly integrating the optical engine and ASIC chip in the same package. This packaging method can effectively improve the functional density and bandwidth of the system while reducing power consumption, latency and cost. It is one of the key technical approaches to solve the problem of massive data transmission in future big data processing and high-speed computing. In the optoelectronic co-packaging structure, the selection of the interposer material is crucial to optical transmission and packaging density.

[0065] At present, the existing interposer materials are mainly divided into organic materials, silicon materials and glass materials. In contrast, glass materials stand out in optoelectronic co-packaging technology due to their superior optical properties and high-frequency characteristics. Glass materials have a low coefficient of thermal expansion and excellent optical transparency, and are particularly suitable for high-precision, low-loss optical waveguide production. Compared with organic materials, it exhibits higher thermal stability and mechanical strength, and is also superior to silicon materials in terms of processability and cost control. Therefore, optoelectronic glass interposers with integrated waveguides, electrical redistribution layers (RDLs) and through-glass vias (TGVs) are strong competitors for CPO advanced packaging materials.

[0066] However, optical waveguides made of glass materials have certain limitations in refractive index control. The refractive index is usually weak, which leads to the bending radius of the optical waveguide reaching the millimeter level and the device size being large. This limitation directly affects the density of chip packaging, making it difficult to achieve high integration within a limited packaging space. This is also a key challenge in the current application of glass interposer technology in CPO.

[0067] Corning uses an ion exchange process to form a single-layer optical waveguide in alkali-containing glass for routing and transmission of optical signals. And the optical waveguide can achieve effective connection with optical fibers and other photonic devices. The silicon photonic chip is integrated on the surface of the glass interposer by mounting, and the optical signal between the two is transmitted through an evanescent wave coupler. To ensure efficient coupling of the signal between the two, the tip length of the coupler is about 2.5 mm.

[0068] However, the glass interposer faces the problem of limited integration density when realizing optical interconnection. First, due to the low refractive index contrast of the glass waveguide, the ability to bind the light field is weaker and the bending radius of the waveguide is larger, which makes the device larger. Secondly, the mode field of the glass waveguide is quite different from the mode field of the waveguide of materials such as silicon, silicon nitride, and lithium niobate, resulting in a longer coupling length. These two factors limit the number of devices that can be packaged on a single glass substrate, making it difficult to achieve higher density integration.

[0069] Figure 1A A partial structural diagram of the optoelectronic co-packaging structure provided for related technologies, such as Figure 1A As shown, the optoelectronic co-packaging structure includes: an intermediate layer 2a and at least one chip 1a. The intermediate layer 2a is made of glass, and a plurality of optical waveguides 4a are arranged inside the intermediate layer 2a, wherein the optical waveguides 4a include a first optical waveguide (not shown) made of glass.

[0070] The chip 1 a is disposed on the upper surface of the intermediate layer 2 a , and at least one optical waveguide structure 3 a is disposed inside the chip 1 a .

[0071] Furthermore, the optical waveguide structure 3a includes a second optical waveguide made of glass material and a coupler (not shown), and the coupler is arranged on a side of the second optical waveguide close to the intermediate layer 2a.

[0072] Since the refractive index contrast of the first optical waveguide and the second optical waveguide of the glass material in the optoelectronic co-packaging structure provided in the related art is low, the first optical waveguide and the second optical waveguide have weaker binding ability on the light field, which increases the bending radius of the first optical waveguide and the second optical waveguide, thereby increasing the size of the first optical waveguide and the second optical waveguide, which will lead to the problem of limited integration density of the intermediate layer of the glass material when realizing optical interconnection.

[0073] In addition, compared with the mode fields of optical waveguides of other materials, the mode field distribution of the first optical waveguide and the second optical waveguide of the glass material is relatively divergent, which is not conducive to efficient coupling with waveguides of other materials, and the coupling length of the first optical waveguide and the second optical waveguide of the glass material is relatively long during the coupling process. Therefore, the number of optical waveguides packaged on the glass interposer is limited, resulting in the inability to achieve higher density integration in the optoelectronic co-packaging structure in the related technology.

[0074] In summary, the first optical waveguide, the second optical waveguide, and the intermediate layer 2a made of glass material in the optical waveguide packaging structure provided in the related art have the following deficiencies:

[0075] The refractive index of the first optical waveguide and the second optical waveguide of the glass material is low, so the binding ability of the light field is weak. In addition, the bending radius of the first optical waveguide and the second optical waveguide of the glass material is large, which will cause the size of the first optical waveguide and the second optical waveguide to become larger. In addition, the mode field distribution of the first optical waveguide and the second optical waveguide of the glass material is relatively divergent, which is not conducive to efficient coupling with optical waveguides of other materials, and also causes the coupling length of the first optical waveguide and the second optical waveguide to be longer during the coupling process, thereby making it impossible to achieve higher density integration in the optoelectronic co-packaging structure in the related technology.

[0076] like Figure 1AAs shown, in the optoelectronic co-packaging structure, optical communication is achieved between multiple chips 1a through the optical waveguide route 4a inside the intermediary layer 2a. Different from the electrical signal communication achieved through metal wires in the optoelectronic co-packaging structure, in the process of optical communication, glass optical waveguides are used to achieve functions such as optical path distribution and optical modulation, and the refractive index contrast of the glass optical waveguide is weak and the bending radius is large (for example, in the relevant embodiments, the bending radius of the optical waveguide is as high as mm level), which leads to a larger size of the optical waveguide route 4a inside the intermediary layer 2a, making it impossible for the chip packaging structure in the related technology to achieve higher density integration.

[0077] also, Figure 1B for Figure 1A A schematic diagram comparing the size of the mode field of the glass optical waveguide in the optoelectronic co-packaging structure and the optical waveguide in the chip is provided in FIG. Figure 1B As shown, the mode field size between the glass optical waveguide and the optical waveguide in the chip is quite different. When using evanescent wave coupling, a larger mode field conversion length is required, which leads to the need for larger glass optical waveguides and optical waveguide routing sizes, which makes the size of the optical waveguide routing in the glass interposer too large and limits the high-density integration of the optoelectronic co-packaging structure.

[0078] In order to solve at least one of the above problems, the present application provides an intermediate layer, aiming to provide an optoelectronic co-packaging structure capable of achieving high-density integration.

[0079] Figure 1 A schematic diagram of the structure of an intermediary layer provided in an embodiment of the present application is shown in FIG. Figure 1 As shown, the intermediate layer 2 includes: a substrate 3, a first waveguide layer 4, and a second waveguide layer 5. The substrate 3 includes a glass substrate or a quartz substrate.

[0080] The first waveguide layer 4 is disposed on the substrate 3, and at least one first waveguide structure 40 is disposed in the first waveguide layer 4. The first waveguide structure 40 includes a first optical waveguide 40a.

[0081] Among them, glass has excellent thermal stability, low thermal expansion coefficient and optical transparency, and can support complex optoelectronic integrated systems. At the same time, glass has high mechanical strength and can provide stable physical support. And the glass substrate can be processed by melt drawing, grinding and polishing technology to ensure its smooth surface for deposition / bonding of the first waveguide layer 4 and the second waveguide layer 5.

[0082] In the embodiment of the present application, the first optical waveguide 40a can be used to achieve low-loss transmission between the optical signal intermediary layer 2 and the external medium (such as optical fiber). Since the refractive index of the first optical waveguide 40a is relatively low, the light field binding ability of the first optical waveguide 40a is weak when it is bent, so the first optical waveguide 40a can be used to provide an efficient connection between the optical signal and the external medium.

[0083] In addition, the present application can also process the first optical waveguide 40a on the substrate 3 by ion beam etching, dry etching or ion exchange technology. In order to optimize the optical fiber coupling performance, the size and geometry of the first optical waveguide 40a can be adjusted during the processing.

[0084] The second waveguide layer 5 is arranged on a side of the first waveguide layer 4 away from the substrate 3, and at least one second waveguide structure 50 is arranged in the second waveguide layer 5. The second waveguide structure 50 includes N second optical waveguides 50a, a third optical waveguide, ..., an N+1th optical waveguide, which are sequentially stacked and arranged on a side of the first waveguide layer 4 away from the substrate 3; wherein 1≤N;

[0085] Further, the refractive indexes of the second optical waveguide 50a, the third optical waveguide, . . . , the N+1th optical waveguide increase in sequence, and the refractive index of the second optical waveguide 50a is greater than the refractive index of the first optical waveguide 40a.

[0086] When N=1, the second waveguide structure includes a second optical waveguide 50a disposed on the side of the first waveguide layer 4 away from the substrate 3. The refractive index of the second optical waveguide 50a is greater than the refractive index of the first optical waveguide 40a. The material of the second optical waveguide 50a can be any one or a combination of any of high refractive index materials such as silicon nitride, silicon oxynitride, lithium niobate, silicon, etc.

[0087] This arrangement can solve the problems of weak binding ability of optical waveguides with low refractive index and large difference in mode field between optical waveguides with low refractive index and PICs chips.

[0088] When N>1, the refractive indexes of the second optical waveguide 50a, the third optical waveguide, ..., the N+1th optical waveguide increase in sequence. The materials of the second optical waveguide 50a, the third optical waveguide, ..., the N+1th optical waveguide can be any one or a combination of any of high refractive index materials such as silicon nitride, silicon oxynitride, lithium niobate, silicon, etc.

[0089] In the embodiment of the present application, the second optical waveguide 50a, the third optical waveguide, ..., the N+1th optical waveguide, which are sequentially stacked on the side of the first waveguide layer 4 away from the substrate 3, have their refractive index gradually increased, so that the binding ability of the light field is enhanced, thereby reducing the bending radius of the waveguide, optimizing the mode field matching between the optical signal and the PICs chip, and improving the coupling efficiency.

[0090] The present application uses chemical vapor deposition (CVD), plasma enhanced chemical vapor deposition (PECVD), atomic layer deposition (ALD) or other thin film technologies to deposit the second optical waveguide 50a, the third optical waveguide, ..., the N+1th optical waveguide with different refractive indices layer by layer, which can not only achieve a step-by-step progression of the refractive index, but also accurately control the thickness of each layer of the waveguide according to specific design requirements. Of course, the deposition thickness of the second optical waveguide 50a, the third optical waveguide, ..., the N+1th optical waveguide is usually in the nanometer and micrometer range.

[0091] The interposer 2 provided by the present application can be applied to a chip packaging structure, and the interposer 2 is provided by firstly providing a first waveguide layer 4 on a glass substrate 3, and then providing a second waveguide layer 5 on the first waveguide layer 4, and a second waveguide structure 50 is provided in the second waveguide layer 6, and the second waveguide structure 50 includes N second optical waveguides 50a, third optical waveguides, ..., N+1 optical waveguides which are sequentially stacked and arranged on the side of the first waveguide layer 4 away from the substrate 3, and the refractive indexes of the second optical waveguides 50a, the third optical waveguides, ..., and the N+1 optical waveguides are sequentially increased and are greater than the refractive indexes of the glass substrate and the first optical waveguide. In this arrangement, the glass substrate can be used for connecting an optical signal with an external medium such as an optical fiber, and the second optical waveguides 50a, the third optical waveguides, ..., and the N+1 optical waveguides which are sequentially stacked and arranged on the side of the first waveguide layer 4 away from the substrate 3 in the high-refractive-index second waveguide structure 50 can be used for efficient interconnection with a chip (e.g., a photonic integrated circuit (PICs) chip) arranged on the interposer 2.

[0092] Compared with the optical waveguide made of glass material in the related art, the optical waveguide (second optical waveguide 50a, third optical waveguide, ..., N+1th optical waveguide) stacked and arranged on the side of the first waveguide layer 4 away from the substrate 3 provided in the present application has a refractive index greater than the refractive index of glass, and the arrangement mode in which the refractive index increases successively not only solves the problem of low integration of the interposer and chip packaging structure caused by the large bending radius of the glass optical waveguide in the related art and the large routing size of the optical waveguide, but also solves the problem of long coupling length and large coupling loss caused by the mode field difference between the optical waveguide in the interposer and the optical waveguide in the chip, thereby realizing higher density integration of the chip packaging structure and efficient optical signal transmission modulation.

[0093] In summary, the present application can not only effectively solve the problem of connecting the optical signal with the external optical fiber, but also optimize the transmission path of the optical signal between the photonic integrated circuits by sequentially arranging the first waveguide layer and the second waveguide layer on the glass substrate. Furthermore, the glass substrate layer can provide structural support for the chip packaging structure, the first waveguide layer 4 can be used to connect with the external optical fiber, and the second waveguide layer 5 can provide efficient interconnection for the transmission and modulation of the optical signal between chips. This setting method can realize a highly integrated and high-performance chip co-packaging structure for optoelectronic transmission.

[0094] In some embodiments, the material of the first optical waveguide 40a includes at least one of glass, silicon dioxide, and silicon oxynitride.

[0095] Figure 2 A schematic diagram of a photoelectric co-packaging structure provided in an embodiment of the present application is shown in FIG. Figure 2 As shown, in some embodiments, the interposer provided in the present application can be applied to a chip packaging structure, wherein the chip packaging structure includes at least one chip 1 and an interposer 2, and the chip 1 is arranged on the interposer 2. Further, the chip 1 can be an electronic chip or a photonic chip. An optical waveguide is arranged inside the interposer to realize optical signal transmission between the chips 1.

[0096] In addition, RDL lines and metal bumps (not shown) are arranged on the interposer 2 to realize electrical interconnection between the chip 1 and the outside world. The interposer 2 realizes high-speed photoelectric communication between chips in the same package through RDL lines and optical waveguides.

[0097] Figure 3 A schematic diagram of a coupling structure provided in an embodiment of the present application is shown in FIG. Figure 3 As shown, in some embodiments, the first optical waveguide 40a and the second optical waveguide 50a are coupled to form a coupling structure.

[0098] Coupling refers to the phenomenon that when the first optical waveguide 40a and the second optical waveguide 50a are close to each other, the "disturbance" of one waveguide on the other waveguide affects the distribution of the light field in the original waveguide. This interaction causes the light energy to be transferred or exchanged between the two waveguides, thereby achieving the distribution and multiplexing of optical signals.

[0099] In the embodiment of the present application, the coupling structure formed by coupling between the first optical waveguide 40a and the second optical waveguide 50a is used to efficiently transmit the optical signal from the first optical waveguide 40a to the second optical waveguide 50a, or to efficiently transmit the optical signal from the second optical waveguide 50a to the first optical waveguide 40a. This coupling structure utilizes the evanescent wave coupling of the optical field between different waveguides to ensure that the optical signal can be coupled in a low-loss manner.

[0100] Furthermore, in the second waveguide layer 5, the width and height of the second optical waveguide 40a gradually narrow along the coupling direction. This arrangement can reduce the confinement capability of the second optical waveguide 40a on the light field, so that part of the light field can overflow into the surrounding space during the process of the second optical waveguide 40a gradually narrowing, and thus enter the first waveguide layer.

[0101] Similarly, in the first waveguide layer 4, the width / height of the first optical waveguide 40a gradually widens along the coupling direction. In this arrangement, by increasing the width of the first optical waveguide 40a, the first optical waveguide 40a enhances the ability to bind the light field, thereby capturing the light field escaping from the second optical waveguide 50a. Since the second optical waveguide 50a has a higher refractive index, the optical signal is gradually transferred from the second optical waveguide 50a to the first optical waveguide 40a, thereby completing the coupling of the optical signal.

[0102] Figure 4 A schematic diagram of a transmission path in an optical signal intermediary layer 2 provided in an embodiment of the present application, Figure 5 A schematic diagram of a transmission path of an optical signal in a chip co-packaging structure provided in an embodiment of the present application, such as Figure 4 and Figure 5 As shown, in some embodiments, the first waveguide structure 40 further includes: a first optical coupler, the first optical coupler (not shown) is arranged on a side of the first optical waveguide 40a close to and / or away from the substrate 3. And / or, the second waveguide structure 50 further includes: a second optical coupler 60, the second optical coupler 60 is arranged on a side of the second optical waveguide 50a close to and / or away from the first optical waveguide 40a.

[0103] Further, the first optical coupler includes: one of a grating coupler, an end face coupler, and a spot converter, and / or the second optical coupler 60 includes: one of a grating coupler, an end face coupler, and a spot converter.

[0104] In the embodiment of the present application, the intermediate layer further includes: an optical element 70, and the optical element 70 is configured to cooperate with the first waveguide structure and / or the second waveguide structure to perform light transmission.

[0105] Furthermore, the optical element 70 also includes a micro-nano lens.

[0106] In some embodiments, Figure 1As shown, the first optical waveguide 40a includes: a first cladding 400, a first core layer 401, and a first protective layer 402. The first cladding 400 is arranged on the substrate 3, the first core layer 401 is arranged on the side of the first cladding 400 away from the substrate 3, and the first protective layer 402 is arranged on the side of the first core layer 401 away from the first cladding 400. And / or, the second optical waveguide 50a includes: a second cladding 500, a second core layer 501, and a second protective layer 502. The second cladding 500 is arranged on the first protective layer 402, the second core layer 501 is arranged on the side of the second cladding 500 away from the first protective layer 402, and the second protective layer 502 is arranged on the side of the second core layer 501 away from the second cladding 500.

[0107] Further, the refractive index of the first cladding layer 400 and the first protective layer 402 is lower than the refractive index of the first core layer 401, and the refractive index of the second cladding layer 500 and the second protective layer 502 is lower than the refractive index of the second core layer 501. The materials of the first cladding layer 400, the first protective layer 402, the second cladding layer 500, and the second protective layer 502 include silicon dioxide or other materials with a refractive index lower than the first core layer 401 or the second core layer 501.

[0108] In some embodiments, the interposer 2 further includes: at least one through hole V, and the through hole V runs through the interposer 2. The orthographic projection of the through hole V on the substrate 3 does not overlap with the orthographic projections of the first waveguide structure 40 and the second waveguide structure 50 on the substrate 3.

[0109] Further, the through hole V includes a first through hole V1 and a second through hole V2 that are interconnected, and the orthographic projection of the first through hole V1 on the substrate 3 covers the orthographic projection of the second through hole V2 on the substrate 3 .

[0110] In some embodiments, the intermediate layer 2 further includes an electrode 8 , wherein the electrode 8 is disposed in the second waveguide layer 5 , and an orthographic projection of the electrode 8 on the substrate 3 partially overlaps with an orthographic projection of the second waveguide structure on the substrate 3 .

[0111] The present application also provides an optoelectronic co-packaging structure, which includes: at least one chip, an RDL line, and the intermediate layer 2 in the above embodiment, and the chip 1 is arranged in the first through hole V1 of the intermediate layer 2, the RDL line is arranged in the second through hole V2 of the intermediate layer 2, and one end of the RDL line is electrically connected to the chip 1 through the first through hole V1, and the other end is electrically connected to the circuit board through the second through hole V2.

[0112] Figure 6 A schematic diagram of a process for preparing an optoelectronic co-packaging structure provided in an embodiment of the present application, Figure 7 A schematic diagram of a process for preparing a photoelectric co-packaging structure provided in an embodiment of the present application is shown in FIG. Figure 6 and Figure 7 As shown, the method includes:

[0113] S1. Form a first waveguide layer on a glass substrate or a quartz substrate, and use a dry etching process to etch at least one first waveguide structure on the first waveguide layer to form the first waveguide layer; the first waveguide structure includes a first optical waveguide.

[0114] S2. Form a second waveguide layer on the first waveguide layer, and use a dry etching process to etch at least one second waveguide structure on the second waveguide layer to form a second waveguide layer; the second waveguide structure includes N second optical waveguides, third optical waveguides, ..., N+1th optical waveguides stacked in sequence on a side of the first waveguide layer away from the substrate; wherein 1≤N; the refractive indexes of the second optical waveguide, the third optical waveguide, ..., the N+1th optical waveguide increase in sequence, and the refractive index of the second optical waveguide is greater than the refractive index of the first optical waveguide.

[0115] S3. Depositing electrodes in the second waveguide layer, and etching on the second waveguide layer, penetrating the second waveguide layer to the substrate, to form a through hole; wherein the through hole comprises a first through hole and a second through hole interconnected with each other; and the orthographic projection of the first through hole on the substrate covers the orthographic projection of the second through hole on the substrate.

[0116] The through hole V is used to realize the electrical interconnection of the chip.

[0117] Preferably, the electrode 8 may be a metal electrode for electro-optical modulation.

[0118] S4. A chip and an RDL line are respectively arranged in the first through hole and the second through hole, and one end of the RDL line is electrically connected to the chip through the first through hole, and the other end of the RDL line is electrically connected to the circuit board through the second through hole.

[0119] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions that a person skilled in the art can think of within the technical scope disclosed in the present application should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. An interposer, characterized in that: include: A substrate, wherein the substrate comprises a glass substrate or a quartz substrate; A first waveguide layer, wherein the first waveguide layer is disposed on the substrate, and at least one first waveguide structure is disposed in the first waveguide layer; the first waveguide structure comprises a first optical waveguide; a second waveguide layer, wherein the second waveguide layer is arranged on a side of the first waveguide layer away from the substrate, and at least one second waveguide structure is arranged in the second waveguide layer; the second waveguide structure comprises N second optical waveguides, a third optical waveguide, ..., an N+1th optical waveguide, which are sequentially stacked and arranged on a side of the first waveguide layer away from the substrate; wherein 1≤N; The refractive indexes of the second optical waveguide, the third optical waveguide, ..., and the N+1th optical waveguide increase in sequence, and the refractive index of the second optical waveguide is greater than the refractive index of the first optical waveguide.

2. The interposer according to claim 1, characterized in that: The first optical waveguide and the second optical waveguide are coupled to form a coupling structure.

3. The interposer according to claim 1, characterized in that: The first waveguide structure further includes: a first optical coupler, the first optical coupler being arranged on a side of the first optical waveguide close to and / or away from the substrate; and / or, The second waveguide structure further includes: a second optical coupler, the second optical coupler being arranged on a side of the second optical waveguide close to and / or away from the first optical waveguide; Also includes: The optical element is configured to cooperate with the first waveguide structure and / or the second waveguide structure to transmit light.

4. The interposer according to claim 1, characterized in that: The material of the first optical waveguide includes at least one of glass, silicon dioxide, and silicon oxynitride.

5. The interposer according to claim 1, characterized in that: The first optical waveguide comprises: a first cladding layer, the first cladding layer being disposed on the substrate; A first core layer, the first core layer is arranged on a side of the first cladding layer away from the substrate; a first protective layer, the first protective layer being arranged on a side of the first core layer away from the first cladding layer; and / or, The second optical waveguide comprises: a second cladding layer, the second cladding layer being disposed on the first protective layer; a second core layer, the second core layer being arranged on a side of the second cladding layer away from the first protective layer; A second protective layer is provided on a side of the second core layer away from the second cladding layer.

6. The interposer according to claim 1, characterized in that: Also includes: at least one through hole, the through hole penetrating the interposer; The orthographic projection of the through hole on the substrate does not overlap with the orthographic projections of the first waveguide structure and the second waveguide structure on the substrate.

7. The interposer according to claim 6, characterized in that: The through hole comprises a first through hole and a second through hole which are interconnected; The orthographic projection of the first through hole on the substrate covers the orthographic projection of the second through hole on the substrate.

8. The interposer according to claim 1, characterized in that: Also includes: An electrode is provided in the second waveguide layer, and an orthographic projection of the electrode on the substrate partially overlaps with an orthographic projection of the second waveguide structure on the substrate.

9. An optoelectronic co-packaging structure, characterized in that: include: At least one chip, an RDL line, and an interposer according to any one of claims 1 to 8; The chip is arranged in a first through hole of the interposer, the RDL line is arranged in a second through hole of the interposer, and one end of the RDL line is electrically connected to the chip through the first through hole, and the other end is electrically connected to the circuit board through the second through hole.

10. A method for preparing an optoelectronic co-packaging structure, characterized in that: include: Forming a first waveguide layer on a glass substrate or a quartz substrate, etching at least one first waveguide structure on the first waveguide layer by a dry etching process, and forming the first waveguide layer; the first waveguide structure includes a first optical waveguide; A second waveguide layer is formed on the first waveguide layer, and at least one second waveguide structure is etched on the second waveguide layer by a dry etching process to form the second waveguide layer; the second waveguide structure comprises N second optical waveguides, third optical waveguides, ..., N+1 optical waveguides which are sequentially stacked and arranged on a side of the first waveguide layer away from the substrate; wherein 1≤N; the refractive indexes of the second optical waveguides, the third optical waveguides, ..., N+1 optical waveguides are increased sequentially, and the refractive index of the second optical waveguide is greater than the refractive index of the first optical waveguide; Depositing electrodes in the second waveguide layer, and etching on the second waveguide layer, penetrating the second waveguide layer to the substrate, to form a through hole; wherein the through hole comprises a first through hole and a second through hole interconnected with each other; and the orthographic projection of the first through hole on the substrate covers the orthographic projection of the second through hole on the substrate; A chip and an RDL line are respectively arranged in the first through hole and the second through hole, and one end of the RDL line is electrically connected to the chip through the first through hole, and the other end of the RDL line is electrically connected to the circuit board through the second through hole.

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