Optical chip packaging structure

Abstract

The present invention discloses an optical chip packaging structure, comprising: an optical chip, a transparent plastic sealing layer, an opaque plastic sealing layer and a packaging substrate, wherein the optical chip is fixed on the packaging substrate, the transparent plastic sealing layer covers the optical chip, the opaque plastic sealing layer covers the upper surface of the transparent plastic sealing layer, one side of the transparent plastic sealing layer is a light incident surface, a light detection surface is provided on the top of the optical chip, and the transparent plastic sealing layer is provided with a light guiding structure located above the light detection surface, which deflects the light entering from the light incident surface to the light detection surface. The present invention deflects the light entering from the light incident surface on the side through the light guiding structure, so that the light is incident on the light detection surface located on the upper surface of the optical chip. This reduces the thickness of the package and provides a larger feeding window for external light. At the same time, since the light guiding structure deflects the optical fiber entering from the side to the upper surface of the optical chip, there is no need to set the light detection surface on the side of the optical chip, which reduces the alignment accuracy requirements and provides greater convenience for subsequent mass production.

Description

Technical Field

[0001] The present invention relates to the technical field related to optical chips, and in particular to an optical chip packaging structure. Background Art

[0002] In some sensing, communication, and computing scenarios, light is fed into the optical chip through optical fibers or other means. In a large number of application scenarios, the light feeding optical path is located on the side of the optical chip. However, the light detection surface of the optical chip is set on the front of the optical chip. Therefore, the solution of the prior art is to redirect the light through a prism or vertically redirect the optical fiber so that it is incident from the top of the front of the optical chip to the light detection surface on the front of the optical chip. This type of packaging requires deflecting the optical fiber by 90°, or using a prism or other device to deflect the light to the light detection surface on the front of the chip. Therefore, the optical chip packaging structure of the prior art occupies a large space and is not easy to integrate. Summary of the Invention

[0003] Based on this, it is necessary to provide an optical chip packaging structure to address the technical problems of the existing optical chip packaging structure occupying a large space and being difficult to integrate.

[0004] The present invention provides an optical chip packaging structure, comprising: an optical chip, a transparent plastic sealing layer, an opaque plastic sealing layer and a packaging substrate, wherein the optical chip is fixed on the packaging substrate, the transparent plastic sealing layer covers the optical chip, the opaque plastic sealing layer covers the upper surface of the transparent plastic sealing layer, one side of the transparent plastic sealing layer is a light incident surface, a light detection surface is provided on the top of the optical chip, and the transparent plastic sealing layer is provided with a light guiding structure located above the light detection surface and deflecting light entering from the light incident surface to the light detection surface.

[0005] Furthermore, the light-guiding structure is a grating structure protruding toward the optical chip.

[0006] Furthermore, the other side surface of the transparent plastic sealing layer opposite to the light incident surface is a reflective surface, and the opaque plastic sealing layer covers the reflective surface.

[0007] Furthermore, a reflective layer is sputtered between the transparent plastic sealing layer and the opaque plastic sealing layer.

[0008] Furthermore, the reflective layer is a metal sputtered on the surface of the transparent plastic packaging layer.

[0009] Furthermore, the metal is titanium, tungsten, aluminum, gold, copper or silver.

[0010] Furthermore, the light-guiding structure covers or partially covers the light-detecting surface.

[0011] Furthermore, the opaque plastic sealing layer is a black plastic sealing layer.

[0012] Furthermore, the packaging substrate is an organic substrate, a ceramic substrate or a frame substrate.

[0013] Furthermore, a plurality of the optical chips are fixed on the packaging substrate, and the transparent plastic packaging layer is provided with one or more light guide structures.

[0014] The present invention uses a light-guiding structure to deflect light entering from the side of the optical chip, directing it to the detector surface located on the top surface of the optical chip. This reduces the package thickness and provides a larger window for external light to enter. Furthermore, because the light-guiding structure deflects optical fiber entering from the side onto the top surface of the optical chip, it eliminates the need for a detector surface located on the side of the optical chip, reducing alignment accuracy requirements and significantly facilitating subsequent mass production. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 This is a structural schematic diagram of an optical chip packaging structure according to an embodiment of the present invention;

[0016] Figure 2 This is a schematic structural diagram of an optical chip packaging structure according to another embodiment of the present invention;

[0017] Figure 3 This is a schematic diagram of an optical chip mounting process of an optical chip packaging structure preparation process according to an embodiment of the present invention;

[0018] Figure 4 This is a schematic diagram of preparing a transparent plastic sealing layer in a process of preparing an optical chip packaging structure according to an embodiment of the present invention;

[0019] Figure 5 This is a schematic diagram of a pre-cutting process for preparing an optical chip packaging structure according to an embodiment of the present invention;

[0020] Figure 6 This is a schematic diagram of preparing a reflective layer in a process of preparing an optical chip packaging structure according to an embodiment of the present invention;

[0021] Figure 7 This is a schematic diagram of preparing an opaque plastic sealing layer in a process of preparing an optical chip packaging structure according to an embodiment of the present invention;

[0022] Figure 8 This is a schematic diagram of finished product cutting during the preparation process of an optical chip packaging structure according to an embodiment of the present invention.

[0023] Marking Description

[0024] 1- Optical chip; 11- Inspection surface; 2- Transparent plastic layer; 21- Light guide structure; 22- Light incident surface; 23- Reflection surface; 24- Cutting groove; 3- Opaque plastic layer; 4- Packaging substrate; 5- Reflection layer; 6- Bonding wire; 7- Light; 8- Middle cutting path. DETAILED DESCRIPTION

[0025] The following further describes specific embodiments of the present invention with reference to the accompanying drawings. Like components are denoted by like reference numerals. It should be noted that the terms "front," "rear," "left," "right," "up," and "down" used in the following description refer to directions in the accompanying drawings, and the terms "inward" and "outward" refer to directions toward or away from the geometric center of a particular component, respectively.

[0026] like Figure 1 The figure shows a structural schematic diagram of an optical chip packaging structure according to an embodiment of the present invention, comprising: an optical chip 1, a transparent plastic sealing layer 2, an opaque plastic sealing layer 3 and a packaging substrate 4, wherein the optical chip 1 is fixed on the packaging substrate 4, the transparent plastic sealing layer 2 covers the optical chip 1, the opaque plastic sealing layer 3 covers the upper surface of the transparent plastic sealing layer 2, one side of the transparent plastic sealing layer 2 is a light incident surface 22, a light detection surface 11 is provided on the top of the optical chip 1, and the transparent plastic sealing layer 2 is provided with a light guiding structure 21 located above the light detection surface 11, which deflects light entering from the light incident surface 22 to the light detection surface 11.

[0027] Specifically, embodiments of the present invention provide a compact optical chip packaging structure that improves integration, reduces the difficulty of fiber-optic feedthrough, and allows fiber-optic signals to be fed directly from the side of the package. The optical chip 1 is fixed to the package substrate 4, and the connection method between the optical chip 1 and the package substrate 4 can adopt existing technologies. For example, the optical chip 1 can be assembled on the package substrate 4 in a face-up manner, with bonding wires 6 connecting the signals to the package substrate 4.

[0028] A light-testing surface 11 is provided on the top, for example, upper surface, of the optical chip 1. A transparent encapsulating material is then encapsulated on the optical chip 1 to form a transparent encapsulating layer 2. The transparent encapsulating layer 2 can cover the optical chip 1 and the upper surface of the encapsulating substrate 4. An opaque encapsulating material is then encapsulated on the transparent encapsulating layer 2 to form an opaque encapsulating layer 3. For example, an opaque encapsulating material is encapsulated on the upper surface of the transparent encapsulating layer 2 to form an opaque encapsulating layer 3.

[0029] One side of the transparent plastic encapsulation layer 2 serves as a light incident surface 22, and a light guide structure 21 is provided within the transparent plastic encapsulation layer 2, located above the light detection surface 11. Preferably, the light guide structure 21 is provided on top of the transparent plastic encapsulation layer 2. A plastic encapsulation mold can be made, and a shape corresponding to the light guide structure 21 can be made on the plastic encapsulation mold. The mold is placed on the packaging substrate 4 and covers the optical chip 1. Then, a transparent plastic encapsulation compound is injected, so that the transparent plastic encapsulation compound encapsulates the optical chip 1 and forms a transparent plastic encapsulation layer 2 including the light guide structure 21. Light guide structures 21 of different shapes and densities can be designed as needed.

[0030] The light 7 enters from the light incident surface 22 of the transparent plastic packaging layer 2 and is deflected by the light guiding structure 21 , so that the light 7 is incident on the light detecting surface 11 .

[0031] Compared with the existing packaging method in which the light incident surface is on the front of the chip packaging structure, the light incident surface of this embodiment is on the side of the packaging structure. Therefore, there is no need to deflect the angle of the external optical fiber, nor is there a need for light deflection devices such as prisms, thereby reducing the packaging volume.

[0032] At the same time, the inspection surface 11 of this embodiment is set on the top of the optical chip 1 (i.e., the front of the optical chip 1). Therefore, compared with the inspection surface 11 set on the side of the optical chip 1, the inspection surface 11 of the present invention has a larger area. Since the light enters from the light incident surface 22 on the side of the transparent plastic layer 2, and the chip side area is small, if the inspection surface is set on the side of the optical chip 1, the optical fiber alignment requirements are high, and the alignment accuracy is easily affected by the error parameters of the packaging process. In this embodiment, the light is deflected by the light guide structure 21 and does not need to be aligned with the side of the optical chip. Therefore, its feeding window is larger, the optical fiber assembly has a larger error tolerance, and the plastic packaging material provides good protection for the optical chip.

[0033] The present invention uses a light-guiding structure to deflect light entering from the side light-entering surface, allowing the light to be incident on the light-detecting surface located on the upper surface of the optical chip. This reduces the package thickness and provides a larger feed window for external light. At the same time, because the light-guiding structure deflects the optical fiber entering from the side to the upper surface of the optical chip, there is no need to set the light-detecting surface on the side of the optical chip, which reduces the alignment accuracy requirements and provides greater convenience for subsequent mass production.

[0034] like Figure 2 The figure shows a structural schematic diagram of an optical chip packaging structure in another embodiment of the present invention, comprising: an optical chip 1, a transparent plastic sealing layer 2, an opaque plastic sealing layer 3 and a packaging substrate 4, wherein the optical chip 1 is fixed on the packaging substrate 4, the transparent plastic sealing layer 2 covers the optical chip 1, the opaque plastic sealing layer 3 covers the upper surface of the transparent plastic sealing layer 2, one side of the transparent plastic sealing layer 2 is a light incident surface 22, a light detection surface 11 is provided on the top of the optical chip 1, the transparent plastic sealing layer 2 is provided with a light guiding structure 21 located above the light detection surface 11, and deflecting light entering from the light incident surface 22 to the light detection surface 11, the light guiding structure 21 is a grating structure protruding toward the optical chip 1, the light guiding structure 21 covers or partially covers the light detection surface 11, the other side of the transparent plastic sealing layer 2 opposite to the light incident surface 22 is a reflective surface 23, the opaque plastic sealing layer 3 covers the reflective surface 23, and the opaque plastic sealing layer 3 is a black plastic sealing layer;

[0035] A reflective layer 5 is sputtered between the transparent plastic sealing layer 2 and the opaque plastic sealing layer 3. The reflective layer 5 is a metal sputtered on the surface of the transparent plastic sealing layer 2. The metal is titanium, tungsten, aluminum, gold, copper or silver.

[0036] The packaging substrate 4 is an organic substrate, a ceramic substrate or a frame substrate.

[0037] Specifically, the light-guiding structure 21 is a grating structure. At the same time, in order to increase the incidence of light on the light-detecting surface 11, a layer of metal is sputtered on the upper surface of the transparent plastic encapsulation layer 2 and / or the reflective surface 23 opposite the incident light, as a reflective layer 5, to reduce the loss of incident light. Preferably, the reflective layer 5 is sputtered on the outer surface of the transparent plastic encapsulation layer 2 including the upper surface of the light-guiding structure 21 and the reflective surface 23. The reflective layer 5 is a metal sputtered on the outer surface of the transparent plastic encapsulation layer 2. The metal material can be titanium (Ti), tungsten (W), aluminum (Al), gold (Au), copper (Cu), silver (Ag) and other metals.

[0038] The opaque plastic sealing layer 3 is a black plastic sealing layer sealed with a black plastic sealing material. The packaging substrate 4 can be an organic substrate, a ceramic substrate or a frame substrate.

[0039] In one embodiment, a plurality of the optical chips 1 are fixed on the packaging substrate 4 , and the transparent plastic packaging layer 2 is provided with one or more light guide structures 21 .

[0040] Specifically, the optical chip packaging structure may be a multi-chip package, and multiple optical chips 1 may be fixed on the packaging substrate 4 by stacking, tiling, or the like.

[0041] like Figures 3 to 8 The preparation method of the optical chip packaging structure of this embodiment specifically includes:

[0042] (1) Figure 3 As shown, multiple optical chips 1 are mounted on the packaging substrate 4 respectively, and are connected to the packaging substrate 4 through bonding wires 6 for signal connection. The optical chips 1 can be stacked in multiple layers or tiled in multiple chips.

[0043] (2) Figure 4 As shown, plastic encapsulation is performed, and a shape corresponding to the grating structure is made on the top of the plastic encapsulation mold. Grating structures of different shapes and different densities can be designed as needed. The plastic encapsulation mold is placed on the packaging substrate 4 and covers all the optical chips 1. A transparent plastic encapsulation material is injected into the plastic encapsulation mold for plastic encapsulation. After curing, a transparent plastic encapsulation layer 2 containing a grating structure is formed, and the grating structure serves as a light guiding structure 21. Since multiple optical chips 1 are covered, multiple shapes corresponding to the grating structure are set on the top of the plastic encapsulation mold. The projection of each shape corresponding to the grating structure on the packaging substrate 4 covers or partially covers one optical chip 1.

[0044] (3) Figure 5 As shown, after curing, an offset pre-cut is performed on the transparent plastic encapsulation layer 2, with the cutting depth being less than or equal to the thickness of the transparent plastic encapsulation layer 2, to form a cutting groove 24. The cutting groove 24 is located near one side of the optical chip 1. This cutting groove can also be formed in a plastic encapsulation mold, with the shape of the cutting groove 24 being fabricated on the mold and then directly formed after plastic encapsulation.

[0045] (4) Figure 6 As shown, a layer of metal is sputtered on the upper surface of the transparent plastic layer 2 and in the cutting groove 24 as a reflective layer 5. The metal of the reflective layer 5 can increase light reflection. The metal material is Ti, W, Al, Ag, Au and other metals.

[0046] (5) Figure 7 As shown, after the sputtering of the reflective layer 5 is completed, an opaque plastic material, such as a black plastic material, is continued to be plasticized on the upper surface of the reflective layer 5 to cover the upper surface of the transparent plastic layer 2 and the reflective layer 5 in the cutting groove 24 to form an opaque plastic layer 3.

[0047] (6) Figure 8 As shown, the finished product is cut along the middle cutting line 8 between the two optical chips 1, completely cutting through the plastic packaging material and the substrate to form a single package.

[0048] This embodiment integrates the grating structure into the optical chip package, providing a larger input window for external light, reducing alignment accuracy requirements and greatly facilitating subsequent mass production. Furthermore, the addition of a reflective layer reduces incident light loss.

[0049] The above-described embodiments merely illustrate several implementations of the present invention, and while their descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that a person skilled in the art would be able to make numerous variations and improvements without departing from the spirit of the present invention, all of which fall within the scope of protection of the present invention. Therefore, the scope of protection of the present invention shall be determined by the appended claims.

Claims

1. An optical chip packaging structure, characterized in that: include: An optical chip (1), a transparent plastic encapsulation layer (2), an opaque plastic encapsulation layer (3) and a packaging substrate (4), wherein the optical chip (1) is fixed on the packaging substrate (4), the transparent plastic encapsulation layer (2) covers the optical chip (1), the opaque plastic encapsulation layer (3) covers the upper surface of the transparent plastic encapsulation layer (2), one side of the transparent plastic encapsulation layer (2) is a light incident surface (22), a light detection surface (11) is provided on the top of the optical chip (1), and the transparent plastic encapsulation layer (2) is provided with a light guide structure (21) located above the light detection surface (11) and deflecting light entering from the light incident surface (22) to the light detection surface (11); The light-guiding structure (21) covers the light-detecting surface (11), and the light-guiding structure (21) is a grating structure protruding toward the optical chip (1).

2. The optical chip packaging structure according to claim 1, wherein: The other side surface of the transparent plastic sealing layer (2) opposite to the light incident surface (22) is a reflective surface (23), and the opaque plastic sealing layer (3) covers the reflective surface (23).

3. The optical chip packaging structure according to any one of claims 1 to 2, characterized in that: A reflective layer (5) is sputtered between the transparent plastic sealing layer (2) and the opaque plastic sealing layer (3).

4. The optical chip packaging structure according to claim 3, wherein: The reflective layer (5) is a metal sputtered on the surface of the transparent plastic sealing layer (2).

5. The optical chip packaging structure according to claim 4, characterized in that: The metal is titanium, tungsten, aluminum, gold, copper or silver.

6. The optical chip packaging structure according to claim 1, wherein: The opaque plastic sealing layer (3) is a black plastic sealing layer.

7. The optical chip packaging structure according to claim 1, wherein: The packaging substrate (4) is an organic substrate or a ceramic substrate.

8. The optical chip packaging structure according to claim 1, wherein: A plurality of the optical chips (1) are fixed on the packaging substrate (4), and the transparent plastic sealing layer (2) is provided with one or more light guide structures (21).

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