WO2023226153A1

WO2023226153A1 - Optical chip package structure and optical chip packaging method

Info

Publication number: WO2023226153A1
Application number: PCT/CN2022/103335
Authority: WO
Inventors: 石先玉; 孙瑜; 万里兮; 吴昊
Original assignee: 成都万应微电子有限公司
Priority date: 2022-05-24
Filing date: 2022-07-01
Publication date: 2023-11-30

Abstract

An optical chip (1) package structure and an optical chip (1) packaging method. The package structure comprises an optical chip (1), a transparent plastic package layer (2), a non-transparent plastic package layer (3) and a package substrate (4), wherein the optical chip (1) is fixed to the package substrate (4); the transparent plastic package layer (2) covers the optical chip (1); the non-transparent plastic package layer (3) covers an upper surface of the transparent plastic package layer (2); one side surface of the transparent plastic package layer (2) is a light-incident surface (22); the top of the optical chip (1) is provided with a light detection surface (11); and the transparent plastic package layer (2) is provided with a light guide structure (21), which is located above the light detection surface (11) and deflects light entering from the light-incident surface (22) to reach the light detection surface (11). The light entering from the light-incident surface (22) of the side surface is deflected by means of the light guide structure (21), such that the light is incident to the light detection surface (11) located on an upper surface of the optical chip (1), thereby reducing the package thickness and providing a larger feed window for external light. In addition, there is no need to arrange the light detection surface (11) on a side surface of the optical chip (1), such that the requirements for alignment precision are lowered.

Description

Optical chip packaging structure, optical chip packaging method

Technical field

The present invention relates to the technical field related to optical chips, in particular to an optical chip packaging structure and an optical chip packaging method.

Background technique

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 feed path is located on the side of the optical chip. However, the light detection surface of the optical chip is arranged on the front side of the optical chip. Therefore, the solution in the existing technology is to divert the light through a prism or vertically through an optical fiber, and then incident the light from above the front of the optical chip to the light detection surface on the front of the optical chip. This kind of packaging requires deflecting the optical fiber by 90°, or using a prism or other device to deflect the light incident on the light detection surface on the front of the chip. Therefore, the existing optical chip packaging structure occupies a large space and is difficult to integrate.

Contents of the invention

Based on this, it is necessary to provide an optical chip packaging structure and an optical chip packaging method in view of the technical problems that the existing optical chip packaging structure occupies a large space and is difficult to integrate.

In one aspect, the present invention provides an optical chip packaging structure, including: an optical chip, a transparent plastic layer, an opaque plastic layer and a packaging substrate. The optical chip is fixed on the packaging substrate, and the transparent plastic layer covers the optical chip. Chip, the opaque plastic layer covers the upper surface of the transparent plastic layer, one side of the transparent plastic layer is the light incident surface, the top of the optical chip is provided with a light detection surface, and the transparent plastic layer is provided with A light guide structure located above the light detection surface and deflecting light entering from the light incident surface to the light detection surface.

Further, the light guide structure is a grating structure protruding toward the optical chip.

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

Furthermore, a reflective layer is sputtered between the transparent plastic layer and the opaque plastic layer.

Furthermore, the reflective layer is metal sputtered on the surface of the transparent plastic sealing layer.

Still further, the metal is titanium, tungsten, aluminum, gold, copper or silver.

Further, the light guide structure covers or partially covers the light detection surface.

Further, the opaque plastic sealing layer is a black plastic sealing layer.

Further, the packaging substrate is an organic substrate, a ceramic substrate or a frame substrate.

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

Another aspect of the present invention provides an optical chip packaging method, including:

Mount multiple optical chips with light detection surfaces on the top on the packaging substrate;

The plastic mold is placed on the packaging substrate and covers the optical chip. The plastic mold is made with a light guide structure shape corresponding to the light guide structure. A transparent plastic material is injected into the plastic mold for plastic sealing. After solidification, a light guide structure containing A light guide structure and a transparent plastic sealing layer covering the optical chip;

The upper surface of the transparent plastic sealing layer is sealed with opaque plastic sealing material, and an opaque plastic sealing layer is formed after solidification;

Cutting is performed between the two optical chips, and the opaque plastic layer, the transparent plastic layer and the packaging substrate are cut to obtain a single packaged plastic structure including the optical chip, the transparent plastic layer, the opaque plastic layer and the packaging substrate.

Further, the plastic mold is made with a plurality of light guide structure shapes corresponding to the light guide structure. When the plastic mold is placed on the packaging substrate, each light guide structure shape corresponding to the light guide structure covers or partially covers one The optical chip.

Further, the light guide structure is a grating structure, and the plastic mold is produced with a light guide structure shape corresponding to the grating structure.

Further, the upper surface of the transparent plastic sealing layer is sealed with an opaque plastic sealing material, and after solidification, an opaque plastic sealing layer is formed, which specifically includes:

A reflective layer is sputtered on the upper surface of the transparent plastic layer;

The upper surface of the reflective layer is sealed with an opaque plastic sealing material, and after solidification, an opaque plastic sealing layer is formed.

Furthermore, sputtering a reflective layer on the upper surface of the transparent plastic layer specifically includes:

Pre-cut the upper surface of the transparent plastic sealing layer to form a cutting groove;

A reflective layer is sputtered on the upper surface of the transparent plastic sealing layer and in the cutting groove.

Furthermore, the plastic mold is placed on the packaging substrate and covers the optical chip. The plastic mold is made with a light guide structure shape corresponding to the light guide structure. A transparent plastic compound is injected into the plastic mold. Plastic sealing, which forms a transparent plastic sealing layer containing the light guide structure after curing, including:

A plastic mold is placed on the packaging substrate and covers the optical chip. The plastic mold is made with a light guide structure shape corresponding to the light guide structure and a cutting groove shape corresponding to the cutting groove. Inject the plastic mold into the mold. The transparent plastic sealing material is molded and solidified to form a transparent plastic sealing layer containing a light guide structure and cutting grooves;

The sputtering of a reflective layer on the upper surface of the transparent plastic sealing layer specifically includes: sputtering a reflective layer on the upper surface of the transparent plastic sealing layer and the cutting groove.

Furthermore, the depth of the cutting groove is less than or equal to the thickness of the transparent plastic sealing layer.

Furthermore, the cutting grooves have a preset distance from the center line of two adjacent optical chips, and all the cutting grooves are close to the optical chips on the same side;

Cutting is performed between the two optical chips, and the opaque plastic layer, the transparent plastic layer and the packaging substrate are cut to obtain a single packaged plastic structure including the optical chip, the transparent plastic layer, the opaque plastic layer and the packaging substrate. Specifically, include:

Cut along the center line of two adjacent optical chips to cut through the opaque plastic layer, the transparent plastic layer and the packaging substrate to obtain a single packaged plastic structure including the optical chip, the transparent plastic layer, the opaque plastic layer and the packaging substrate.

Furthermore, the sputtering of a reflective layer specifically includes: sputtering a layer of metal as the reflective layer.

Furthermore, the metal is titanium, tungsten, aluminum, gold, copper or silver, etc.

The invention uses a light guide structure to deflect the light entering from the light incident surface on the side, so that the light enters the light detection surface located on the upper surface of the optical chip. This reduces package thickness and provides a larger feed window for external light. At the same time, since the light guide 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 of the drawings

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

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

Figure 3 is a work flow chart of an optical chip packaging method according to an embodiment of the present invention;

Figure 4 is a work flow chart of an optical chip packaging method according to another embodiment of the present invention;

Figure 5 is a schematic diagram of optical chip mounting during the preparation process of a plastic packaging structure according to an embodiment of the present invention;

Figure 6 is a schematic diagram of a transparent plastic sealing layer preparation process of a plastic sealing structure preparation process according to an embodiment of the present invention;

Figure 7 is a pre-cut schematic diagram of the preparation process of a plastic packaging structure according to an embodiment of the present invention;

Figure 8 is a schematic diagram of the reflective layer preparation process of a plastic packaging structure according to an embodiment of the present invention;

Figure 9 is a schematic diagram of the preparation process of the opaque plastic sealing layer of a plastic sealing structure according to an embodiment of the present invention;

Figure 10 is a schematic diagram of finished product cutting during the preparation process of a plastic packaging structure according to an embodiment of the present invention;

Figure 11 is a work flow chart of an optical chip packaging method according to the preferred embodiment of the present invention.

Tag description

1-optical chip; 11-light detection surface; 2-transparent plastic sealing layer; 21-light guide structure; 22-light incident surface; 23-reflective surface; 24-cutting groove; 3-opaque plastic sealing layer; 4-packaging substrate; 5-Reflective layer; 6-Bonding wire; 7-Light; 8-Middle cutting channel.

Detailed ways

The present invention will be described in further detail below in conjunction with the accompanying drawings and specific embodiments.

Figure 1 is a schematic structural diagram of an optical chip packaging structure according to an embodiment of the present invention, including: an optical chip 1, a transparent plastic layer 2, an opaque plastic layer 3 and a packaging substrate 4. The optical chip 1 is fixed on the On the packaging substrate 4, the transparent plastic layer 2 covers the optical chip 1, the opaque plastic layer 3 covers the upper surface of the transparent plastic layer 2, and one side of the transparent plastic layer 2 is the 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 above the light detection surface 11 to deflect the light entering from the light incident surface 22 to the light detection surface 11. The light guide structure 21 on the surface 11.

Specifically, embodiments of the present invention provide a compact optical chip packaging structure, which can improve integration, reduce the difficulty of fiber feeding, and feed fiber signals directly from the side of the package. Among them, the optical chip 1 is fixed on the packaging substrate 4, and the connection method between the optical chip 1 and the packaging substrate 4 can adopt existing technology. For example, the optical chip 1 can be assembled on the packaging substrate 4 in a formal assembly manner, and the bonding wire 6 performs signal connection with the packaging substrate 4 .

The top of the optical chip 1 , for example, the upper surface, is provided with a light detection surface 11 . Then, a transparent plastic compound is encapsulated on the optical chip 1 to form a transparent plastic layer 2 . The transparent plastic encapsulation layer 2 can cover the optical chip 1 and the upper surface of the packaging substrate 4 . The opaque plastic sealing material is then packaged on the transparent plastic sealing layer 2 to form an opaque plastic sealing layer 3 . For example, the upper surface of the transparent plastic layer 2 is covered with an opaque plastic material to form the opaque plastic layer 3 .

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

The light 7 enters from the light incident surface 22 of the transparent plastic sealing layer 2 and is deflected by the light guide structure 21 so that the light 7 is incident on the light detection surface 11 .

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 in this embodiment is on the side of the packaging structure. Therefore, there is no need to deflect the angle of the external optical fiber, and no light deflection devices such as prisms are needed. The package size is reduced.

At the same time, the photodetection surface 11 of this embodiment is disposed on the top of the optical chip 1 (that is, the front surface of the optical chip 1). Therefore, the photodetection surface 11 of the present invention has a larger area than if it is disposed on the side of the optical chip 1. Since light enters from the light incident surface 22 on the side of the transparent plastic sealing layer 2, and the chip side area is smaller, if the light detection surface is set on the side of the optical chip 1, the optical fiber alignment requirements are higher, and the alignment accuracy is easily affected by the packaging. Influence of process error parameters. In this embodiment, the light is deflected through the light guide structure 21 and does not need to be aligned with the side of the optical chip. Therefore, the feed window is larger and the optical fiber assembly has a greater error tolerance. At the same time, the plastic packaging material forms a good seal on the optical chip. protection of.

The invention uses a light guide structure to deflect the light entering from the light incident surface on the side, so that the light enters the light detection surface located on the upper surface of the optical chip. This reduces package thickness and provides a larger feed window for external light. At the same time, since the light guide 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 can provide greater convenience for subsequent mass production.

Figure 2 is a schematic structural diagram of an optical chip packaging structure in another embodiment of the present invention, including: an optical chip 1, a transparent plastic layer 2, an opaque plastic layer 3 and a packaging substrate 4. The optical chip 1 is fixed on On the packaging substrate 4, the transparent plastic layer 2 covers the optical chip 1, the opaque plastic layer 3 covers the upper surface of the transparent plastic layer 2, and one side of the transparent plastic layer 2 is inlet. Light 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 above the light detection surface 11 to deflect the light entering from the light incident surface 22 to the light detection surface 11. The light guide structure 21 of the light detection surface 11, the light guide structure 21 is a grating structure protruding toward the direction of the optical chip 1, the light guide structure 21 covers or partially covers the light detection surface 11, the transparent The other side of the 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, and the opaque plastic sealing layer 3 is a black plastic sealing layer;

A reflective layer 5 is sputtered between the transparent plastic layer 2 and the opaque plastic layer 3 . The reflective layer 5 is metal sputtered on the surface of the transparent plastic layer 2 .

In one embodiment, the metal is titanium, tungsten, aluminum, gold, copper or silver.

In one embodiment, the packaging substrate 4 is an organic substrate, a ceramic substrate or a frame substrate.

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

The opaque plastic sealing layer 3 is a black plastic sealing layer sealed with black plastic sealant. The packaging substrate 4 may be an organic substrate, a ceramic substrate or a frame substrate.

In one embodiment, a plurality of 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 .

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 other methods.

Figures 5 to 10 illustrate the preparation method of the optical chip packaging structure of this embodiment, which specifically includes:

(1) As shown in Figure 5, multiple optical chips 1 are mounted on the packaging substrate 4 respectively, and signal connections are made with the packaging substrate 4 through bonding wires 6. The optical chips 1 can be multi-layer stacks or multi-chip flat. shop;

(2) As shown in Figure 6, plastic molding is performed, and a shape corresponding to the grating structure is made on the top of the plastic mold. Grating structures of different shapes and different density levels can be designed according to needs. The plastic mold is placed on the packaging substrate 4 and covers all the optical chips 1. A transparent plastic compound is injected into the plastic mold for plastic sealing. After curing, a transparent plastic layer 2 containing a grating structure is formed. The grating structure serves as the light guide structure 21. Since multiple optical chips 1 are covered, multiple shapes corresponding to the grating structures are set on the top of the plastic mold. The projection of each shape corresponding to the grating structure on the packaging substrate 4 covers or partially covers one optical chip 1 .

(3) As shown in FIG. 7 , offset pre-cutting is performed on the transparent plastic sealing layer 2 after curing, and the cutting depth is less than or equal to the thickness of the transparent plastic sealing layer 2 to form a cutting groove 24 . The cutting groove 24 is close to the optical chip 1 on one side. The formation of the cutting groove can also be realized on the plastic mold. The shape of the cutting groove 24 is made on the mold, and the cutting groove 24 is formed directly after plastic sealing.

(4) As shown in Figure 8, a layer of metal is sputtered on the upper surface of the transparent plastic layer 2 and in the cutting groove 24 as the reflective layer 5. The metal of the reflective layer 5 can increase light reflection. The metal materials are Ti, W, Al, Ag, Au and other metals.

(5) As shown in Figure 9, after the sputtering of the reflective layer 5 is completed, the upper surface of the reflective layer 5 continues to be covered with an opaque plastic material, such as a black plastic material, to cover the upper surface of the transparent plastic layer 2 and the reflection in the cutting groove 24. Layer 5 forms an opaque plastic sealing layer 3.

(6) As shown in Figure 10, the finished product is cut along the middle cutting track 8 between the two optical chips 1, and the plastic packaging material and substrate are completely cut to form a single package.

By fabricating the grating structure within the optical chip packaging structure, this embodiment provides a larger feed window for external light, reduces alignment accuracy requirements, and provides greater convenience for subsequent mass production. At the same time, by adding a reflective layer, the incident light loss is reduced.

Figure 3 shows a work flow chart of an optical chip packaging method according to an embodiment of the present invention, which includes:

Step S301, mount multiple optical chips 1 with light detection surfaces 11 on the top on the packaging substrate 4;

Step S302: Place a plastic mold on the packaging substrate 4 and cover the optical chip 1. The plastic mold is made with a light guide structure shape corresponding to the light guide structure 21. A transparent plastic material is injected into the plastic mold. Plastic sealing, after curing, a transparent plastic sealing layer 2 containing the light guide structure 21 and covering the optical chip 1 is formed;

Step S303, seal the upper surface of the transparent plastic sealing layer 2 with an opaque plastic sealant, and then solidify to form an opaque plastic sealant layer 3;

Step S304: Cut between the two optical chips 1 and cut the opaque plastic layer 3, the transparent plastic layer 2 and the packaging substrate 4 to obtain a single package including the optical chip 1, the transparent plastic layer 2 and the opaque plastic layer 3 and a plastic packaging structure of the packaging substrate 4 .

The optical chip packaging method of this embodiment can use packaging and the plastic packaging structure described above.

Figure 1 is a schematic structural diagram of a plastic packaging structure according to an embodiment of the present invention, including: an optical chip 1, a transparent plastic layer 2, an opaque plastic layer 3 and a packaging substrate 4. The optical chip 1 is fixed on the packaging substrate. 4, the transparent plastic layer 2 covers the optical chip 1, the opaque plastic layer 3 covers the upper surface of the transparent plastic layer 2, and one side of the transparent plastic layer 2 is the 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 above the light detection surface 11 to deflect the light entering from the light incident surface 22 to the light detection surface 11. light guide structure 21.

Specifically, step S301 is performed, and the optical chip 1 is fixed on the packaging substrate 4. The connection method between the optical chip 1 and the packaging substrate 4 can adopt existing technology. For example, the optical chip 1 can be assembled on the packaging substrate 4 in a flip-chip or front-mounted manner, and signal connections are made with the packaging substrate 4 through flip-chip bumps or bonding wires 6 . Among them, the top of the optical chip 1, such as the upper surface, is provided with a light detection surface 11. The packaging substrate 4 is an organic substrate, a ceramic substrate or a frame substrate.

Then, step S302 is performed to encapsulate the optical chip 1 with a transparent plastic compound through a pre-made plastic mold to form a transparent plastic layer 2 . The transparent plastic encapsulation layer 2 can cover the optical chip 1 and the upper surface of the packaging substrate 4 . The existing mold making method can be used to make the light guide structure shape corresponding to the light guide structure 21 in the plastic mold. The mold is placed on the packaging substrate 4 and covers the optical chip 1 , and then a transparent plastic compound is injected, so that the transparent plastic compound encapsulates the optical chip 1 and forms a transparent plastic layer 2 including a light guide structure 21 . Light guide structures 21 with different light guide structure shapes and different density levels can be designed as needed. Preferably, a light guide structure shape corresponding to the light guide structure 21 is provided on the top of the plastic mold, so that the light guide structure 21 is formed on the top of the transparent plastic layer 2 after curing.

Then, step S303 is performed to encapsulate the opaque plastic material on the transparent plastic layer 2 to form the opaque plastic layer 3 . For example, the upper surface of the transparent plastic layer 2 is covered with an opaque plastic material to form the opaque plastic layer 3 . The opaque plastic sealing material is preferably black plastic sealing material, and a black opaque plastic sealing layer 3 is formed after curing.

Finally, step S304 is performed to cut between the two optical chips 1, and cut the opaque plastic layer 3, the transparent plastic layer 2 and the packaging substrate 4 to obtain a single package including the optical chip 1, the transparent plastic layer 2, the opaque The plastic packaging layer 3 and the plastic packaging structure of the packaging substrate 4.

Preferably, cutting is performed on the center line between the two optical chips 1 to obtain a single package plastic structure. Specifically, it can be cut according to the single packaging requirements. If the plastic packaging structure of the single package includes one optical chip 1, then the plastic packaging structure is cut to include one optical chip 1. If the plastic packaging structure of a single package includes multiple optical chips 1, the plastic packaging structure is cut to include multiple optical chips 1.

As shown in Figure 1, during use, one side of the transparent plastic sealing layer 2 is used as the light incident surface 22. The light 7 enters from the light incident surface 22 of the transparent plastic sealing layer 2 and is guided by the light guide located above the light detection surface 11. The structure 21 deflects the light 7 so that it is incident on the light detection surface 11 .

The present invention prepares a light guide structure in a transparent plastic sealing layer, so that the prepared plastic sealing structure can deflect the light entering from the side light incident surface through the light guide structure, so that the light is incident on the light detection surface located on the upper surface of the optical chip. This reduces package thickness and provides a larger feed window for external light. At the same time, since the light guide 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.

Figure 4 shows a work flow chart of an optical chip packaging method in another embodiment of the present invention, including:

Step S401, mount multiple optical chips 1 with light detection surfaces 11 on the top on the packaging substrate 4;

Step S402: Place a plastic mold on the packaging substrate 4 and cover the optical chip 1. The plastic mold is made with a light guide structure shape corresponding to the light guide structure 21. A transparent plastic material is injected into the plastic mold. Plastic sealing, after curing, forms a transparent plastic sealing layer 2 that contains the light guide structure 21 and covers the optical chip 1. The plastic sealing mold is made with a plurality of light guide structure shapes corresponding to the light guide structure 21. Place the plastic sealing mold on When packaging the substrate 4, each light guide structure shape corresponding to the light guide structure 21 covers or partially covers one of the optical chips 1. The light guide structure 21 is a grating structure, and the plastic mold is made with a shape corresponding to the grating structure. The shape of the light guide structure;

Step S403, sputter a layer of reflective layer 5 on the upper surface of the transparent plastic layer 2;

In one embodiment, a reflective layer 5 is sputtered on the upper surface of the transparent plastic layer 2, which specifically includes:

Pre-cut the upper surface of the transparent plastic sealing layer 2 to form cutting grooves 24;

A reflective layer 5 is sputtered on the upper surface of the transparent plastic layer 2 and in the cutting groove 24 .

In one embodiment, the depth of the cutting groove 24 is less than or equal to the thickness of the transparent plastic sealing layer 2 .

In one embodiment, sputtering a layer of reflective layer 5 specifically includes: sputtering a layer of metal as the reflective layer 5 .

Step S404, the upper surface of the reflective layer 5 is plastic-sealed with an opaque plastic material, and after solidification, an opaque plastic layer 3 is formed;

Step S405: Cut between the two optical chips 1 and cut the opaque plastic layer 3, the transparent plastic layer 2 and the packaging substrate 4 to obtain a single package including the optical chip 1, the transparent plastic layer 2 and the opaque plastic layer 3 and a plastic packaging structure of the packaging substrate 4 .

In one embodiment, the cutting grooves 24 have a preset distance from the center line of two adjacent optical chips 1, and all the cutting grooves 24 are close to the optical chips 1 on the same side;

Cutting is performed between the two optical chips 1, and the opaque plastic sealing layer 3, the transparent plastic sealing layer 2 and the packaging substrate 4 are cut to obtain a single package including the optical chip 1, the transparent plastic sealing layer 2, the opaque plastic sealing layer 3 and The plastic packaging structure of the packaging substrate 4 specifically includes:

Cut along the center line of two adjacent optical chips 1, cut through the opaque plastic sealing layer 3, the transparent plastic sealing layer 2 and the packaging substrate 4, and obtain a single package including the optical chip 1, the transparent plastic sealing layer 2, the opaque plastic sealing layer 3 and The plastic packaging structure of the packaging substrate 4.

Specifically, FIG. 2 is a schematic structural diagram of a plastic packaging structure in another embodiment of the present invention, including: an optical chip 1, a transparent plastic layer 2, an opaque plastic layer 3 and a packaging substrate 4. The optical chip 1 Fixed on the packaging substrate 4, the transparent plastic layer 2 covers the optical chip 1, the opaque plastic layer 3 covers the upper surface of the transparent plastic layer 2, and one side of the transparent plastic layer 2 As the light incident surface 22, a light detection surface 11 is provided on the top of the light chip 1, and the transparent plastic sealing layer 2 is provided above the light detection surface 11 to deflect the light entering from the light incident surface 22 to The light guide structure 21 of the light detection surface 11 is a grating structure protruding toward the light chip 1, and the light guide structure 21 covers or partially covers the light detection surface 11, so The other side of the transparent plastic layer 2 opposite to the light incident surface 22 is a reflective surface 23, and the opaque plastic layer 3 covers the reflective surface 23, and the opaque plastic layer 3 is a black plastic layer;

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

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

Specifically, the plastic packaging structure may be a multi-chip package, and multiple optical chips 1 may be fixed on the packaging substrate 4 by stacking, tiled, or other methods.

Figures 5 to 10 illustrate the preparation method of the plastic packaging structure of this embodiment, which specifically includes:

(1) Execute step S401, as shown in Figure 5, mount multiple optical chips 1 with light detection surfaces 11 on the top respectively on the packaging substrate 4, and perform signal connection with the packaging substrate 4 through the bonding wires 6, The optical chip 1 can be a multi-layer stack or multi-chip tile;

(2) Execute step S402, as shown in Figure 6, plastic molding, and make a light guide structure shape corresponding to the grating structure on the top of the plastic mold. Grating structures with different light guide structure shapes and different density levels can be designed as needed. The plastic mold is placed on the packaging substrate 4 and covers all the optical chips 1. A transparent plastic compound is injected into the plastic mold for plastic sealing. After curing, a transparent plastic layer 2 containing a grating structure is formed. The grating structure serves as the light guide structure 21. Since multiple optical chips 1 are covered, multiple light guide structure shapes corresponding to the grating structures are set on the top of the plastic mold. The projection of each light guide structure shape corresponding to the grating structure on the packaging substrate 4 covers or partially covers an optical chip 1 .

(3) Step S403 is performed. As shown in FIG. 7 , offset pre-cutting is performed on the transparent plastic sealing layer 2 after solidification. The cutting depth is less than or equal to the thickness of the transparent plastic sealant layer 2 to form a cutting groove 24 . The cutting groove 24 is close to the optical chip 1 on one side. The cutting groove can also be formed on a plastic mold. The shape of the light guide structure of the cutting groove 24 is made on the mold, and the cutting groove 24 is formed directly after plastic sealing.

In one embodiment, the plastic mold is placed on the packaging substrate 4 and covers the optical chip 1. The plastic mold is made with a light guide structure shape corresponding to the light guide structure 21. In the plastic mold A transparent plastic sealing material is injected into the medium for plastic sealing, and after curing, a transparent plastic sealing layer 2 containing the light guide structure 21 is formed, which specifically includes:

A plastic mold is placed on the packaging substrate 4 and covers the optical chip 1. The plastic mold is made with a light guide structure shape corresponding to the light guide structure 21 and a cutting groove shape corresponding to the cutting groove 24. The transparent plastic sealing material is injected into the plastic sealing mold for plastic sealing, and after curing, a transparent plastic sealing layer 2 including the light guide structure 21 and the cutting groove 24 is formed;

The sputtering of a reflective layer 5 on the upper surface of the transparent plastic sealing layer 2 specifically includes: sputtering a reflective layer 5 on the upper surface of the transparent plastic sealant layer 2 and in the cutting groove 24 .

The setting of the cutting groove 24 is set according to the requirements of the single package. For example, if the plastic packaging structure of the single package only includes one optical chip 1, then the cutting groove 24 is provided between two adjacent optical chips 1. If the plastic packaging structure of a single package includes multiple optical chips 1, a cutting groove 24 is provided next to the optical chip 1 located at the edge of the plastic packaging structure, and the cutting groove 24 is located at the edge of the cut plastic packaging structure.

In addition, the cutting grooves 24 have a preset distance from the center line of two adjacent optical chips 1 , and all the cutting grooves 24 are close to the optical chips 1 on the same side. For example, all the cutting grooves 24 are between two adjacent optical chips 1 and are close to the left optical chip 1, or all the cutting grooves 24 are between two adjacent optical chips 1 and are close to the right optical chip 1. At the same time, the preset distance between the cutting groove 24 and the center line of the two adjacent optical chips 1 is greater than the thickness of the middle cutting track 8 , and the middle cutting track 8 is arranged along the center line of the two adjacent optical chips 1 . Therefore, when cutting along the middle cutting lane 8 , the same side of the molded structure includes the cutting groove 24 , and the other side does not include the cutting groove 24 . As shown in Figure 10, when cutting along the middle cutting lane 8 of two adjacent optical chips 1, there are no cutting grooves 24 on the left side of all plastic packaging structures, while the cutting grooves 24 are reserved on the right sides, so that on the left side of the plastic packaging structure Light can be fed in as the light incident surface 22, while the right side of the cutting groove 24 is retained as the reflective surface 23.

Then, as shown in Figure 8, a layer of metal is sputtered on the upper surface of the transparent plastic layer 2 and in the cutting groove 24 as the reflective layer 5. The metal of the reflective layer 5 can increase light reflection, and the metal materials are Ti, W, Al, and Ag. , Au and other metals. If the reflective layer 5 is not provided in the final product, this step can be omitted.

(4) Execute step S404. As shown in Figure 9, after completing the sputtering of the reflective layer 5, continue to pass the opaque plastic material, such as black plastic material, on the upper surface of the reflective layer 5 to cover the upper surface of the transparent plastic layer 2 and the cutting groove. The reflective layer 5 in 24 forms an opaque plastic sealing layer 3.

(6) Step S405 is executed. As shown in Figure 10, the finished product is cut. Cut along the middle cutting lane 8 between the two optical chips 1 to completely cut the plastic packaging material and the substrate to form a single package.

As shown in Figure 11, the best embodiment of the present invention is an optical chip packaging method, including:

Step S1101, as shown in Figure 5, chip mounting and wire bonding;

Step S1102, as shown in Figure 6, the transparent plastic sealing material is sealed, the grating is formed, and a transparent plastic sealing layer is formed after curing;

Step S1103, as shown in Figure 7, pre-cut the transparent plastic sealing layer to form cutting grooves;

Step S1104, as shown in Figure 8, a metal layer is sputtered on the surface of the transparent plastic layer as a reflective layer;

Step S1105, as shown in Figure 9, use opaque plastic sealing material for the second plastic sealing, and form an opaque plastic sealing layer after solidification;

Step S1106, as shown in Figure 10, perform cutting and sorting.

This embodiment provides a larger feed window for external light by fabricating the grating structure within the plastic packaging structure, reduces the alignment accuracy requirements, and can provide greater convenience for subsequent mass production. At the same time, by adding a reflective layer, the incident light loss is reduced.

The above-mentioned embodiments only express several implementation modes of the present invention, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the patent scope of the present invention. It should be noted that, for those of ordinary skill in the art, several modifications and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the scope of protection of the patent of the present invention should be determined by the appended claims.

Claims

An optical chip packaging structure, characterized in that it includes: an optical chip (1), a transparent plastic sealing layer (2), an opaque plastic sealing layer (3) and a packaging substrate (4), and the optical chip (1) is fixed on the On the packaging substrate (4), the transparent plastic layer (2) covers the optical chip (1), the opaque plastic layer (3) covers the upper surface of the transparent plastic layer (2), and the transparent plastic layer (3) covers the upper surface of the transparent plastic layer (2). One side of the 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 a light detection surface (11) is provided on the transparent plastic sealing layer (2). (11) Above, a light guide structure (21) that deflects light entering from the light incident surface (22) to the light detection surface (11).
The optical chip packaging structure according to claim 1, wherein the light guide structure (21) is a grating structure protruding toward the optical chip (1).
The optical chip packaging structure according to claim 1, characterized in that the other side 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) Cover the reflective surface (23).
The optical chip packaging structure according to any one of claims 1 to 3, characterized in that a reflective layer (5) is sputtered between the transparent plastic layer (2) and the opaque plastic layer (3).
The optical chip packaging structure according to claim 4, characterized in that the reflective layer (5) is metal sputtered on the surface of the transparent plastic sealing layer (2).
The optical chip packaging structure according to claim 1, characterized in that the light guide structure (21) covers or partially covers the light detection surface (11).
The optical chip packaging structure according to claim 1, characterized in that, 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 Describe the light guide structure (21).
An optical chip packaging method, characterized by including:

Mount multiple optical chips (1) with light detection surfaces (11) on the top on the packaging substrate (4);

A plastic mold is placed on the packaging substrate (4) and covers the optical chip (1). The plastic mold is made with a light guide structure shape corresponding to the light guide structure (21). A transparent mold is injected into the plastic mold. The plastic sealing material is molded and solidified to form a transparent plastic sealing layer (2) that contains the light guide structure (21) and covers the optical chip (1);

The upper surface of the transparent plastic sealing layer (2) is sealed with an opaque plastic sealing material, and after solidification, an opaque plastic sealing layer (3) is formed;

Cutting is performed between the two optical chips (1), and the opaque plastic sealing layer (3), transparent plastic sealing layer (2) and packaging substrate (4) are cut to obtain a single package including the optical chip (1), transparent plastic sealing The plastic packaging structure includes the layer (2), the opaque plastic packaging layer (3) and the packaging substrate (4).
The optical chip packaging method according to claim 8, characterized in that the plastic mold is made with a plurality of light guide structure shapes corresponding to the light guide structure (21), and the plastic mold is placed on the packaging substrate (4) At this time, each light guide structure shape corresponding to the light guide structure (21) covers or partially covers one of the optical chips (1).
The optical chip packaging method according to claim 8, characterized in that the light guide structure (21) is a grating structure, and the plastic mold is produced with a light guide structure shape corresponding to the grating structure.
The optical chip packaging method according to claim 8, characterized in that the upper surface of the transparent plastic layer (2) is plastic-sealed with an opaque plastic material, and the opaque plastic layer (3) is formed after solidification, specifically including:

Sputter a layer of reflective layer (5) on the upper surface of the transparent plastic sealing layer (2);

The upper surface of the reflective layer (5) is plastic-sealed with an opaque plastic material, and after solidification, an opaque plastic layer (3) is formed.
The optical chip packaging method according to claim 11, characterized in that sputtering a reflective layer (5) on the upper surface of the transparent plastic layer (2) specifically includes:

Pre-cut the upper surface of the transparent plastic sealing layer (2) to form a cutting groove (24);

A reflective layer (5) is sputtered on the upper surface of the transparent plastic layer (2) and in the cutting groove (24).
The optical chip packaging method according to claim 8, characterized in that the plastic mold is placed on the packaging substrate (4) and covers the optical chip (1), and the plastic mold is made with a light guide structure (21) According to the shape of the light guide structure, a transparent plastic sealant is injected into the plastic mold for plastic sealing, and after curing, a transparent plastic sealant layer (2) containing the light guide structure (21) is formed, which specifically includes:

The plastic mold is placed on the packaging substrate (4) and covers the optical chip (1). The plastic mold is made with a light guide structure shape corresponding to the light guide structure (21) and a cutting groove (24). The shape of the cutting groove is formed by injecting a transparent plastic compound into the plastic mold for plastic sealing, and after curing, a transparent plastic layer (2) including the light guide structure (21) and the cutting groove (24) is formed;

The sputtering of a reflective layer (5) on the upper surface of the transparent plastic layer (2) specifically includes: sputtering a reflective layer (5) on the upper surface of the transparent plastic layer (2) and the cutting groove (24). ).
The optical chip packaging method according to claim 12 or 13, characterized in that the depth of the cutting groove (24) is less than or equal to the thickness of the transparent plastic sealing layer (2).
The optical chip packaging method according to claim 12 or 13, characterized in that the cutting groove (24) has a preset distance from the center line of two adjacent optical chips (1), and all the cutting grooves ( 24) The optical chip (1) close to the same side;

Cutting is performed between the two optical chips (1), and the opaque plastic sealing layer (3), transparent plastic sealing layer (2) and packaging substrate (4) are cut to obtain a single package including the optical chip (1), The plastic packaging structure of the transparent plastic sealing layer (2), the opaque plastic sealing layer (3) and the packaging substrate (4) specifically includes:

Cut along the center line of two adjacent optical chips (1), cut the opaque plastic layer (3), the transparent plastic layer (2) and the packaging substrate (4) to obtain a single package including the optical chip (1), A plastic packaging structure of a transparent plastic sealing layer (2), an opaque plastic sealing layer (3) and a packaging substrate (4).