Effective reduction of multiple bad packaging process, structure and material of FA fiber array module

Abstract

The application discloses a process, structure and material for effectively reducing multiple bad encapsulation of a FA fiber array module, which comprises the following steps: S1, a plurality of V-shaped grooves are arranged on the upper surface layer of a quartz substrate, optical fibers are placed in the V-shaped grooves of the quartz substrate, and a cover plate is placed on the quartz substrate; S2, the quartz substrate is placed in a plastic encapsulation mold; S3, epoxy plastic encapsulation material is filled into the plastic encapsulation mold, and the epoxy plastic encapsulation material is heated and solidified to form a plastic encapsulation film layer; and S4, the plastic encapsulation mold is removed, and the encapsulation of the FA fiber array module is completed. The application can effectively avoid the multiple encapsulation bad phenomenon caused by the shrinkage of UV glue during the encapsulation process of the FA optical module; meanwhile, the encapsulation process is effectively simplified, and the encapsulation cost is significantly reduced.

Description

Technical Field

[0001] This invention relates to the field of FA (fiber optic array) optical module packaging technology, and in particular to a packaging process, structure and materials for effectively reducing multiple defective packages in FA fiber optic array modules. Background Technology

[0002] The FA fiber array uses a quartz V-groove substrate, bare optical fibers, a gland, and a MT ferrule as its core packaging structure. UV-cured epoxy adhesive is the sole bonding medium, serving multiple functions including fixation, sealing, and stress buffering. However, during the entire FA packaging process, UV adhesive curing can cause volume shrinkage and linear shrinkage (common UV optical adhesives: 3%~5% or even higher), leading to lens shift, tilt deviation, optical axis misalignment, stress deformation, post-curing drift, defocusing, and decreased yield. Simultaneously, issues such as bubbles, adhesive overflow, incomplete curing, aging failure, and temperature drift also arise. Furthermore, uneven curing / poor curing in shaded areas, and surface-to-internal incomplete curing can occur during UV adhesive curing (structural obstruction causing UV light dead zones, excessive adhesive layer thickness, wavelength mismatch, light source aging / insufficient energy, resulting in surface curing, a soft and sticky underlying layer, residual uncured monomers, subsequent slow post-curing drift, creep displacement, interface corrosion, and long-term strength attenuation). During the use of UV-cured epoxy adhesives, substrate compatibility and interface adhesion issues also exist, with significant mismatches in the CTE (coefficient of thermal expansion) between materials. For example, glass lenses, plastic lenses, and aluminum / ceramic substrates have large differences in CTE, and repeated thermal stress during temperature cycling leads to residual stress in the adhesive layer, resulting in problems such as microcracks, delamination, and lens tilt drift. These issues can cause multiple encapsulation defects during the FA (Fabry-Performance) optical module packaging process, mainly including optical path coupling misalignment, interface delamination, reduced structural reliability, and decreased product batch consistency.

[0003] Modeling technology is the core molding process for discrete devices and various integrated circuits. Using epoxy molding compound (EMC) as the medium, it is a necessary link for the industrialization and large-scale application of chips, and runs through the entire process of traditional packaging and advanced FC-BGA and 2.5D packaging. In the chip packaging structure, the functions of the molding layer mainly include: (1) Core protection function. When the chip die, bonding wire, micro bumps and fine circuits of the substrate are directly exposed, they are easily damaged by moisture, dust, mechanical external force and acid and alkali corrosion. The molten molding compound wraps the components in one piece, forming a dense insulating protective layer, isolating the external environment from interference, improving the device's moisture resistance, shock resistance, temperature resistance and insulation performance, and ensuring the long-term electrical reliability of the chip. (2) Supporting the molding of high-density packaging structures. The low viscosity molding compound has excellent fluidity under high temperature and high pressure, which can fully fill the deep blind holes of the substrate, chip gaps and micro wiring trenches, avoid filling voids and missing glue defects, adapt to high aspect ratio micro-holes and ultra-thin chip stacking structures, ensure the integrity of interlayer interconnection, and meet the high-density wiring requirements of high-end computing power and memory chips. (3) Adaptable to high-volume, low-cost mass production. Molding equipment has a high degree of automation, and multiple products can be molded simultaneously in a single mold cavity. The process parameters are stable and controllable, and the yield is easy to manage. The EMC material system is rich, and low-stress, high-thermal-conductivity, and low-water-absorption formulations can be formulated as needed, compatible with almost all packaging forms such as QFP, SOP, BGA, and flip chips. (4) Provides standardized device shape. After integral molding, the device size and outline can be unified, which is convenient for automated processing of subsequent processes such as lead cutting, marking, testing, and surface mounting, and is compatible with circuit board surface mounting processes. In summary, molding technology takes into account multiple values ​​such as protection, structural molding, mass production, and standardization, and is an indispensable key process for transforming chips from bare dies into commercial finished products.

[0004] In the field of chip packaging, the process flow of Modeling technology mainly includes: (1) Wafer / substrate pretreatment. After chip mounting and bonding, cleaning and impurity removal are carried out to remove oil and particles from the pads and circuit surfaces. Preheating to 160–180℃ ensures interface wettability. (2) Mold closing and injection. The carrier is placed into the upper and lower mold cavities, the mold is closed and locked, and preheated epoxy molding compound EMC is injected. The mainstream transfer molding process is adopted, and the hydraulic push rod pushes the molten resin into the runner under high pressure. (3) High pressure filling molding. The mold temperature is 170–185℃, the injection pressure is 8–15 MPa, the molten resin flows into the cavity along the gate, fully wrapping the chip, gold wire, micro bumps and deep hole structure of the substrate, and holding pressure for 30–90 s to suppress shrinkage voids. (4) In-mold curing: the initial cross-linking curing is completed by constant temperature and pressure holding. Under the locked state, the heating is continued for 2–5 min to reduce the internal stress of the resin and prevent resin backflow and material shortage in the deep hole area. (5) Post-molding treatment: The semi-finished product is ejected from the mold and then cured and baked to achieve cross-linking; then the flash removal, marking, grinding, and rib cutting and separation processes are performed. Modeling technology relies on high temperature and low viscosity resin + continuous high pressure to achieve high aspect ratio micropore filling. High temperature greatly reduces the EMC melt viscosity, and high pressure continuously pushes the resin deep into the blind holes, grooves, and through-silicon via sidewalls of the substrate; the closed mold cavity has no air retention, and with gradient pressure holding, the gas trapped in the hole can be discharged to avoid air bubbles and voids. Compared with the film bonding process, the molding resin has stronger fluidity and can cover structures with smaller hole width and greater depth, stably filling deep holes with an aspect ratio of less than 1:10, with no missing glue at the bottom of the hole and complete coverage of the hole wall; after the resin is cured, it is integrally molded, and there is no delamination problem in the hole.

[0005] Therefore, effectively reducing volume and linear shrinkage during the UV adhesive curing stage in the entire FA (Fabry-Performance) packaging process, thereby minimizing multiple packaging defects caused by UV curing shrinkage, has always been a research hotspot in the field of FA optical module packaging technology. Modeling technology, in advanced chip packaging structures (taking Fan-Out Wafer Level Packaging (FOWLP), Fan-Out Board Level Packaging (FOPLP), and System-in-Package (SiP) as examples), can effectively fill micron-level gaps, eliminate voids caused by air lock-in within the holes, prevent bottom adhesive shortages, and avoid interface delamination. Furthermore, it has classic application cases where the molding layer does not develop voids due to shrinkage after high-temperature baking. Therefore, applying Modeling technology to the FA optical module packaging process can effectively avoid multiple packaging defects caused by shrinkage during UV adhesive curing. Summary of the Invention

[0006] To address the aforementioned technical problems, the present invention aims to provide an effective packaging process, structure, and materials for reducing multiple defects in FA fiber optic array modules. This packaging structure and method can effectively avoid multiple packaging defects caused by UV adhesive curing shrinkage during the FA optical module packaging process; while ensuring the smooth completion of the entire FA optical module packaging process, it can effectively simplify the packaging process and significantly reduce packaging costs.

[0007] To achieve the above technical objectives and effects, this invention provides an effective packaging process for reducing multiple defects in FA fiber array modules, comprising the following steps:

[0008] S1, Several V-shaped grooves are set on the upper surface of the quartz substrate. The optical fiber is placed in the V-shaped groove of the quartz substrate, and the cover plate is placed on the quartz substrate.

[0009] S2, Place the quartz substrate (with optical fiber inside the V-groove) into the molding die;

[0010] S3, fill the mold with epoxy molding compound and heat the epoxy molding compound to cure it, forming a molding film layer;

[0011] S4, Remove the plastic sealant; the FA fiber array module packaging is complete.

[0012] The epoxy molding compound described in step S3 can be in the form of solid, liquid, or sheet; in this embodiment, the epoxy molding compound is in the form of liquid.

[0013] Furthermore, in step S2, the size of the molding die is larger than that of the quartz substrate. The top, front, back, left, and right sides of the quartz substrate are all covered by the molding die, which has a small opening to be filled with epoxy molding compound.

[0014] Furthermore, in step S2, the size of the molding die is equal to the size of the quartz substrate. The upper surface of the quartz substrate is covered by the molding die, which has a small opening for filling with epoxy molding compound.

[0015] According to another aspect of the present invention, an effective packaging structure for reducing multiple defects in FA fiber array modules obtained by the above packaging process includes a quartz substrate, a cover plate, an epoxy molding compound and a molding die, wherein a plurality of V-grooves are provided on the upper surface of the quartz substrate, the optical fiber is placed in the V-grooves of the quartz substrate, and the cover plate is placed on the quartz substrate.

[0016] The quartz substrate is placed in a molding die;

[0017] There are gaps between the optical fiber and the quartz V-groove.

[0018] The epoxy molding compound is filled into the molding mold, filling all gaps, and then heated and cured to form a molding film layer.

[0019] Remove the plastic encapsulation mold to obtain the packaging structure of the FA fiber array module.

[0020] Furthermore, the size of the molding die is larger than that of the quartz substrate. The top, front, back, left, and right sides of the quartz substrate are all covered by the molding die. The molding die has a small opening for filling with epoxy molding compound.

[0021] Furthermore, the size of the molding die is equal to the size of the quartz substrate, the upper surface of the quartz substrate is covered by the molding die, and the molding die has a small opening for filling with epoxy molding compound.

[0022] According to another aspect of the present invention, the present invention provides a packaging material that can effectively reduce multiple packaging defects in FA fiber array modules, including epoxy molding compound. The epoxy molding compound effectively fills the micron-level gaps in the FA optical module packaging structure using modeling technology, eliminating voids caused by air locking within the holes, insufficient adhesive at the bottom, and interface delamination. Furthermore, after high-temperature baking, the molding layer does not shrink and develop voids, thereby effectively reducing the occurrence of multiple packaging defects during the FA optical module packaging process. Simultaneously, compared to UV-curable adhesives, epoxy molding compounds (solid EMC, liquid EMC) are cheaper and have simpler application processes, effectively simplifying the FA packaging process and reducing production costs.

[0023] The beneficial effects of this invention are mainly as follows: (1) By using Modeling technology to replace UV curing adhesive, and after high-temperature baking, the molding layer will not have voids due to shrinkage, thereby effectively reducing the occurrence of multiple encapsulation defects in the FA optical module packaging process; (2) The EMC used is a non-photosensitive material. Compared with the UV curing adhesive process (UV light irradiation curing), epoxy molding material only needs to be heated and baked to complete the complete curing and molding; epoxy molding material is cheaper and the packaging process is simpler, which can significantly reduce the packaging cost; (3) After curing, the molding layer can directly serve as the insulating protective layer (physical protection, chemical protection, water and oxygen isolation, etc.) of the FA fiber array module, without the need for additional glass cover protection, which can effectively simplify the FA fiber array module packaging process and reduce production costs. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of a structure in which an optical fiber is placed in a V-groove on a quartz substrate.

[0025] Figure 2 This is a schematic diagram of a quartz substrate placed in a molding die.

[0026] Figure 3 This is a schematic diagram of a structure for filling epoxy molding compound into the mold through a small opening and then heating and curing the epoxy molding compound.

[0027] Figure 4 A schematic diagram of the structure for removing the plastic sealant.

[0028] Figure 5 This is a schematic diagram of a quartz substrate placed in a molding die.

[0029] Figure 6 This is a schematic diagram of a structure for filling epoxy molding compound into the mold through a small opening and then heating and curing the epoxy molding compound.

[0030] Figure 7 A schematic diagram of the structure for removing the plastic sealant. Detailed Implementation

[0031] The invention will be further described below with reference to the accompanying drawings and embodiments.

[0032] (1) The optical fiber is placed in the V-groove of the quartz substrate to obtain the following result: Figure 1 The structure is shown. 10 is a quartz substrate, and 11 is an optical fiber. Gaps exist between the optical fiber and the quartz V-groove.

[0033] (2) Place the quartz substrate (with optical fiber inside the V-groove) in a molding die to obtain the following result: Figure 2 The structure shown is shown below. 100 represents the molding die. The molding die has a small opening for filling with epoxy molding compound. The molding die is larger than the quartz substrate, meaning that five sides of the quartz substrate are encapsulated by the molding die.

[0034] (3) Epoxy molding compound (liquid molding compound is used as an example) is filled into the molding mold through the small opening on the molding mold, and the epoxy molding compound is heated and cured to obtain the following result: Figure 3 The structure shown is shown. 12 is the cured plastic sealant layer.

[0035] (4) Remove the plastic seal mold to obtain the following: Figure 4 The structure shown is a fully encapsulated FA optical module. Because the size of the molding die is larger than the size of the quartz substrate, the final FA optical module has five sides (top / left / right / front / back) covered by the molding film.

[0036] (5) Place the quartz substrate (with optical fiber inside the V-groove) in the molding die to obtain the following result: Figure 5 The structure shown is shown. 100 represents the molding die. The molding die has a small opening for filling with epoxy molding compound. The size of the molding die is equal to the size of the quartz substrate, meaning only the upper surface of the quartz substrate is covered by the molding die.

[0037] (6) Fill the encapsulation mold with epoxy molding compound (liquid molding compound is used as an example in this embodiment) through the small opening on the encapsulation mold, and heat and cure the epoxy molding compound to obtain the following: Figure 6 The structure shown is shown. 12 is the cured plastic sealant layer.

[0038] (7) Remove the plastic seal mold to obtain the following: Figure 7 The structure shown is a fully packaged FA optical module. Because the size of the molding die is equal to the size of the quartz substrate, only the top surface of the final FA optical module is covered by the molding film layer.

[0039] It will be apparent to those skilled in the art that this invention is not limited to the details of the exemplary embodiments described above, and that it can be implemented in other specific forms without departing from the spirit or essential characteristics of this invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of this invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of the equivalent elements of the claims be included within this invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

Claims

1. A packaging process for effectively reducing multiple defects in FA fiber array modules, characterized in that, Includes the following steps: S1, Several V-shaped grooves are set on the upper surface of the quartz substrate. The optical fiber is placed in the V-shaped groove of the quartz substrate, and the cover plate is placed on the quartz substrate. S2, Place the quartz substrate in the molding die; S3, fill the mold with epoxy molding compound and heat the epoxy molding compound to cure it, forming a molding film layer; S4, Remove the plastic sealant; the FA fiber array module packaging is complete.

2. The packaging process according to claim 1, characterized in that: The epoxy molding compound described in step S3 is in solid, liquid, or sheet form.

3. The packaging process according to claim 2, characterized in that: The epoxy molding compound described in step S3 is in liquid form.

4. The packaging process according to claim 1, characterized in that: In step S2, the size of the molding die is larger than that of the quartz substrate. The top, front, back, left, and right sides of the quartz substrate are all covered by the molding die. The molding die has a small opening to be filled with epoxy molding compound.

5. The packaging process according to claim 1, characterized in that: In step S2, the size of the molding die is larger than the size of the quartz substrate, or the size of the molding die is equal to the size of the quartz substrate. The upper surface of the quartz substrate is covered by the molding die, which has a small opening to be filled with epoxy molding compound.

6. A packaging structure for effectively reducing multiple defects in FA fiber array modules obtained by the packaging process according to any one of claims 1-5, characterized in that: The quartz substrate includes a cover plate, an epoxy molding compound, and a molding mold. The upper surface of the quartz substrate is provided with several V-grooves. The optical fiber is placed in the V-grooves of the quartz substrate, and the cover plate is placed on the quartz substrate. The quartz substrate is placed in a molding die; There are gaps between the optical fiber and the quartz V-groove; The epoxy molding compound is filled into the molding mold, filling all gaps, and then heated and cured to form a molding film layer. Remove the plastic encapsulation mold to obtain the packaging structure of the FA fiber array module.

7. The packaging structure according to claim 6, characterized in that: The molding die is larger than the quartz substrate. The top, front, back, left, and right sides of the quartz substrate are all covered by the molding die. The molding die has a small opening for filling with epoxy molding compound.

8. The packaging structure according to claim 6, characterized in that: The size of the molding die is equal to the size of the quartz substrate. The upper surface of the quartz substrate is covered by the molding die, which has a small opening for filling with epoxy molding compound.

9. A packaging material for effectively reducing multiple defects in the packaging of FA fiber optic array modules, characterized in that, Applied to claim 1 or 6, the epoxy molding compound effectively fills the micron-level gaps in the FA optical module packaging structure using Modeling technology, eliminating voids caused by air locking in the holes, lack of adhesive at the bottom, and no interface delamination. After high-temperature baking, the molding layer will not have voids due to shrinkage, thereby reducing the occurrence of multiple packaging defects during the FA optical module packaging process.

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