Optical chip packaging method
By introducing light guide structure and reflective layer into optical chip package, the problems of large size and high alignment accuracy of optical chip package structure are solved, and a smaller and easy-to-integrate optical chip package is achieved.
Patent Information
- Application Number
- CN202210574671.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2022-05-24
- Publication Date
- 2025-08-12
- Estimated Expiration
- 2042-05-24
AI Technical Summary
The existing optical chip packaging structure occupies a large space and is not easy to integrate. The light feeds into the optical path need to be deflected by 90° or uses prisms and other devices, resulting in large package size and high alignment accuracy requirements.
A light guide structure is introduced into the optical chip package, and the light incident on the side is deflected to the top light detection surface of the optical chip through a transparent plastic sealing layer. The light guide structure is used as a grating structure, and the reflective layer is sputtered on the transparent plastic sealing layer to increase the reflectivity of the light, reduce the package thickness and alignment accuracy requirements.
Reduces package thickness, provides a larger light feed window, reduces alignment accuracy requirements, and simplifies mass production processes.
Smart Images
Figure CN114999937B_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field related to optical chips, and in particular to a plastic 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 optical 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 method, comprising:
[0005] Mounting a plurality of optical chips with a light-detecting surface on the top on a packaging substrate;
[0006] Placing a plastic encapsulation mold on the packaging substrate and covering the optical chip, wherein the plastic encapsulation mold is made with a light guide structure shape corresponding to the light guide structure, injecting a transparent plastic encapsulation material into the plastic encapsulation mold for plastic encapsulation, and forming a transparent plastic encapsulation layer containing the light guide structure and covering the optical chip after curing;
[0007] The upper surface of the transparent plastic sealing layer is sealed with an opaque plastic sealing material, and an opaque plastic sealing layer is formed after solidification;
[0008] Cutting is performed between the two optical chips to cut the opaque plastic sealing layer, the transparent plastic sealing layer and the packaging substrate to obtain a single packaged plastic sealing structure including the optical chip, the transparent plastic sealing layer, the opaque plastic sealing layer and the packaging substrate.
[0009] Furthermore, the plastic encapsulation mold is manufactured with a plurality of light guide structure shapes corresponding to the light guide structure. When the plastic encapsulation mold is placed on the packaging substrate, each light guide structure shape corresponding to the light guide structure covers or partially covers one of the optical chips.
[0010] Furthermore, the light guide structure is a grating structure, and the plastic encapsulation mold is made with a light guide structure shape corresponding to the grating structure.
[0011] Furthermore, the method of molding the upper surface of the transparent molding layer with an opaque molding material to form an opaque molding layer after curing specifically includes:
[0012] Sputtering a reflective layer on the upper surface of the transparent plastic sealing layer;
[0013] The upper surface of the reflective layer is sealed with an opaque sealing material, and an opaque sealing layer is formed after curing.
[0014] Furthermore, the step of sputtering a reflective layer on the upper surface of the transparent plastic sealing layer specifically includes:
[0015] Pre-cutting the upper surface of the transparent plastic sealing layer to form a cutting groove;
[0016] A reflective layer is sputtered on the upper surface of the transparent plastic sealing layer and in the cutting groove.
[0017] Furthermore, the plastic encapsulation mold is placed on the packaging substrate and covers the optical chip, the plastic encapsulation mold is made with a light guide structure shape corresponding to the light guide structure, a transparent plastic encapsulation material is injected into the plastic encapsulation mold for plastic encapsulation, and a transparent plastic encapsulation layer containing the light guide structure is formed after curing, specifically including:
[0018] Placing a plastic encapsulation mold on the packaging substrate and covering the optical chip, wherein the plastic encapsulation 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, injecting a transparent plastic encapsulation material into the plastic encapsulation mold for plastic encapsulation, and forming a transparent plastic encapsulation layer including the light guide structure and the cutting groove after curing;
[0019] The step of sputtering 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 in the cutting groove.
[0020] Furthermore, the depth of the cutting groove is less than or equal to the thickness of the transparent plastic sealing layer.
[0021] Furthermore, the cutting groove has a preset distance from the center line of two adjacent optical chips, and all the cutting grooves are close to the optical chip on the same side;
[0022] The cutting is performed between the two optical chips to cut the opaque plastic sealing layer, the transparent plastic sealing layer and the packaging substrate to obtain a single packaged plastic sealing structure including the optical chip, the transparent plastic sealing layer, the opaque plastic sealing layer and the packaging substrate, specifically comprising:
[0023] Cutting is performed along the center line of two adjacent optical chips to cut the opaque plastic sealing layer, the transparent plastic sealing layer and the packaging substrate to obtain a single packaged plastic sealing structure including the optical chip, the transparent plastic sealing layer, the opaque plastic sealing layer and the packaging substrate.
[0024] Furthermore, the sputtering of a reflective layer specifically includes: sputtering a layer of metal as the reflective layer.
[0025] Furthermore, the metal is titanium, tungsten, aluminum, gold, copper or silver.
[0026] The present invention incorporates a light-guiding structure within the transparent plastic encapsulation layer, enabling the resulting plastic encapsulation structure to deflect light entering from the side light-entering surface, directing it toward the light-detecting 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 fibers entering from the side toward the top surface of the optical chip, the light-detecting surface need not be located on the side of the optical chip, reducing alignment accuracy requirements and significantly facilitating subsequent mass production. BRIEF DESCRIPTION OF THE DRAWINGS
[0027] Figure 1 This is a workflow diagram of an optical chip packaging method according to an embodiment of the present invention;
[0028] Figure 2 This is a structural schematic diagram of a plastic packaging structure according to an embodiment of the present invention;
[0029] Figure 3 This is a workflow diagram of an optical chip packaging method according to another embodiment of the present invention;
[0030] Figure 4 This is a structural schematic diagram of a plastic packaging structure according to another embodiment of the present invention;
[0031] Figure 5 This is a schematic diagram of an optical chip mounting process of a plastic package structure preparation process according to an embodiment of the present invention;
[0032] Figure 6 This is a schematic diagram of preparing a transparent plastic sealing layer in a process of preparing a plastic sealing structure according to an embodiment of the present invention;
[0033] Figure 7 This is a schematic diagram of pre-cutting in a process of preparing a plastic package structure according to an embodiment of the present invention;
[0034] Figure 8 This is a schematic diagram of preparing a reflective layer in a process of preparing a plastic package structure according to an embodiment of the present invention;
[0035] Figure 9 This is a schematic diagram of preparing an opaque plastic sealing layer in a process of preparing a plastic sealing structure according to an embodiment of the present invention;
[0036] Figure 10 This is a schematic diagram of finished product cutting during a process of preparing a plastic package structure according to an embodiment of the present invention;
[0037] Figure 11 This is a workflow diagram of an optical chip packaging method according to the best embodiment of the present invention.
[0038] Marking Description
[0039] 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
[0040] 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.
[0041] like Figure 1 FIG. 1 is a flowchart of a method for packaging an optical chip according to an embodiment of the present invention, comprising:
[0042] Step S101, mounting a plurality of optical chips 1 with a light detection surface 11 on the top on a packaging substrate 4;
[0043] Step S102: placing a plastic encapsulation mold on the packaging substrate 4 and covering the optical chip 1. The plastic encapsulation mold is made with a light guide structure shape corresponding to the light guide structure 21. A transparent plastic encapsulation material is injected into the plastic encapsulation mold for plastic encapsulation. After curing, a transparent plastic encapsulation layer 2 containing the light guide structure 21 and covering the optical chip 1 is formed.
[0044] Step S103, molding the upper surface of the transparent molding layer 2 with an opaque molding material, and forming an opaque molding layer 3 after curing;
[0045] In step S104 , cutting is performed between the two optical chips 1 to cut the opaque plastic sealing layer 3 , the transparent plastic sealing layer 2 and the packaging substrate 4 to obtain a single packaged plastic sealing structure including the optical chip 1 , the transparent plastic sealing layer 2 , the opaque plastic sealing layer 3 and the packaging substrate 4 .
[0046] like Figure 2 The figure shows a structural schematic diagram of a plastic packaging structure according to an embodiment of the present invention, comprising: an optical chip 1, a transparent plastic packaging layer 2, an opaque plastic packaging layer 3 and a packaging substrate 4, wherein the optical chip 1 is fixed on the packaging substrate 4, the transparent plastic packaging layer 2 covers the optical chip 1, the opaque plastic packaging layer 3 covers the upper surface of the transparent plastic packaging layer 2, one side of the transparent plastic packaging 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 packaging 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.
[0047] Specifically, step S101 is performed, where the optical chip 1 is fixed to the packaging substrate 4. The connection method between the optical chip 1 and the packaging substrate 4 can adopt existing technologies. For example, the optical chip 1 can be assembled on the packaging substrate 4 using a flip-chip or face-up method, and the signal connection to the packaging substrate 4 is established via flip-chip bumps or bonding wires 6. A light detection surface 11 is provided on the top, such as the upper surface, of the optical chip 1. The packaging substrate 4 can be an organic substrate, a ceramic substrate, or a frame substrate.
[0048] Then, step S102 is performed, and a transparent encapsulating material is encapsulated on the optical chip 1 through a pre-made encapsulating mold 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. The existing mold making method can be used to make a light-guiding structure shape corresponding to the light-guiding structure 21 in the encapsulating mold. The mold is placed on the encapsulating substrate 4 and covers the optical chip 1, and then the transparent encapsulating material is injected so that the transparent encapsulating material encapsulates the optical chip 1 and forms a transparent encapsulating layer 2 including the light-guiding structure 21. Light-guiding structures 21 with different shapes and different densities can be designed as needed. Preferably, a light-guiding structure shape corresponding to the light-guiding structure 21 is set on the top of the encapsulating mold, so that after curing, the light-guiding structure 21 is formed on the top of the transparent encapsulating layer 2.
[0049] Then, step S103 is performed to further encapsulate an opaque encapsulating material on the transparent encapsulating layer 2 to form an opaque encapsulating layer 3. For example, an opaque encapsulating material is coated on the upper surface of the transparent encapsulating layer 2 to form an opaque encapsulating layer 3. The opaque encapsulating material is preferably a black encapsulating material, which forms a black opaque encapsulating layer 3 after curing.
[0050] Finally, step S104 is executed to cut between the two optical chips 1, cutting the opaque plastic sealing layer 3, the transparent plastic sealing layer 2 and the packaging substrate 4 to obtain a single packaged plastic sealing structure including the optical chip 1, the transparent plastic sealing layer 2, the opaque plastic sealing layer 3 and the packaging substrate 4.
[0051] Preferably, the cut is made along the midline between the two optical chips 1 to obtain a single-package plastic-encapsulated structure. The specific cutting method can be based on the requirements of the single package. If the single-package plastic-encapsulated structure includes one optical chip 1, the plastic-encapsulated structure is cut to include one optical chip 1. If the single-package plastic-encapsulated structure includes multiple optical chips 1, the plastic-encapsulated structure is cut to include multiple optical chips 1.
[0052] like Figure 2 As shown, when in use, one side surface of the transparent plastic sealing layer 2 is used as the light incident surface 22 , and the light 7 enters from the light incident surface 22 of the transparent plastic sealing layer 2 and is deflected by the light guiding structure 21 located above the light detecting surface 11 , so that the light 7 is incident on the light detecting surface 11 .
[0053] 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.
[0054] 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.
[0055] The present invention incorporates a light-guiding structure within the transparent plastic encapsulation layer, enabling the resulting plastic encapsulation structure to deflect light entering from the side light-entering surface, directing it toward the light-detecting 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 fibers entering from the side toward the top surface of the optical chip, the light-detecting surface need not be located on the side of the optical chip, reducing alignment accuracy requirements and significantly facilitating subsequent mass production.
[0056] like Figure 3 FIG. 1 is a flowchart of a method for packaging an optical chip according to another embodiment of the present invention, comprising:
[0057] Step S301, mounting a plurality of optical chips 1 with a light detection surface 11 on the top on a packaging substrate 4;
[0058] Step S302: placing a plastic encapsulation mold on the packaging substrate 4 and covering the optical chip 1; the plastic encapsulation mold is manufactured with a light guide structure shape corresponding to the light guide structure 21; a transparent plastic encapsulation material is injected into the plastic encapsulation mold for plastic encapsulation; after curing, a transparent plastic encapsulation layer 2 is formed that contains the light guide structure 21 and covers the optical chip 1; the plastic encapsulation mold is manufactured with multiple light guide structure shapes corresponding to the light guide structure 21; when the plastic encapsulation mold is placed on the packaging substrate 4, each light guide structure shape corresponding to the light guide structure 21 covers or partially covers one optical chip 1; the light guide structure 21 is a grating structure, and the plastic encapsulation mold is manufactured with a light guide structure shape corresponding to the grating structure;
[0059] Step S303, sputtering a reflective layer 5 on the upper surface of the transparent plastic sealing layer 2;
[0060] In one embodiment, the process of sputtering a reflective layer 5 on the upper surface of the transparent plastic sealing layer 2 specifically includes:
[0061] Pre-cutting the upper surface of the transparent plastic sealing layer 2 to form a cutting groove 24;
[0062] A reflective layer 5 is sputtered on the upper surface of the transparent plastic packaging layer 2 and in the cutting groove 24 .
[0063] 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 .
[0064] In one embodiment, the sputtering of a reflective layer 5 specifically includes: sputtering a layer of metal as the reflective layer 5 .
[0065] In one embodiment, the metal is titanium, tungsten, aluminum, gold, copper or silver.
[0066] Step S304, sealing the upper surface of the reflective layer 5 with an opaque plastic sealing material, and forming an opaque plastic sealing layer 3 after curing;
[0067] In step S305 , cutting is performed between the two optical chips 1 to cut the opaque plastic sealing layer 3 , the transparent plastic sealing layer 2 and the packaging substrate 4 to obtain a single packaged plastic sealing structure including the optical chip 1 , the transparent plastic sealing layer 2 , the opaque plastic sealing layer 3 and the packaging substrate 4 .
[0068] In one embodiment, the cutting groove 24 has a preset distance from the center line of two adjacent optical chips 1, and all the cutting grooves 24 are close to the optical chip 1 on the same side;
[0069] The cutting is performed between the two optical chips 1 to cut the opaque plastic sealing layer 3, the transparent plastic sealing layer 2 and the packaging substrate 4 to obtain a single packaged plastic sealing structure including the optical chip 1, the transparent plastic sealing layer 2, the opaque plastic sealing layer 3 and the packaging substrate 4, specifically comprising:
[0070] Cut along the center line of two adjacent optical chips 1 to cut the opaque plastic sealing layer 3, the transparent plastic sealing layer 2 and the packaging substrate 4 to obtain a single packaged plastic sealing structure including the optical chip 1, the transparent plastic sealing layer 2, the opaque plastic sealing layer 3 and the packaging substrate 4.
[0071] Specifically, if Figure 4The figure shows a structural schematic diagram of a plastic packaging structure in another embodiment of the present invention, comprising: an optical chip 1, a transparent plastic packaging layer 2, an opaque plastic packaging layer 3 and a packaging substrate 4, wherein the optical chip 1 is fixed on the packaging substrate 4, the transparent plastic packaging layer 2 covers the optical chip 1, the opaque plastic packaging layer 3 covers the upper surface of the transparent plastic packaging layer 2, one side of the transparent plastic packaging 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 packaging 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 packaging layer 2 opposite to the light incident surface 22 is a reflective surface 23, the opaque plastic packaging layer 3 covers the reflective surface 23, and the opaque plastic packaging layer 3 is a black plastic packaging layer;
[0072] 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.
[0073] The packaging substrate 4 is an organic substrate, a ceramic substrate or a frame substrate.
[0074] 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.
[0075] 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.
[0076] 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 .
[0077] Specifically, the plastic package structure may be a multi-chip package, and multiple optical chips 1 may be fixed on the package substrate 4 by stacking, laying, or the like.
[0078] like Figures 5 to 10 The preparation method of the plastic package structure of this embodiment specifically includes:
[0079] (1) Execute step S301, such as Figure 5 As shown, multiple optical chips 1 with a light detection surface 11 on the top are mounted on the packaging substrate 4 respectively, and are connected to the packaging substrate 4 for signal connection through bonding wires 6. The optical chips 1 can be stacked in multiple layers or tiled;
[0080] (2) Execute step S302, such as Figure 6 As shown, plastic encapsulation is performed, and a light-guiding structure shape corresponding to the grating structure is made on the top of the plastic encapsulation mold. Different light-guiding structure shapes and grating structures with different densities can be designed as needed. The plastic encapsulation mold is placed on the packaging substrate 4, and all the optical chips 1 are covered. 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 light-guiding structure shapes corresponding to the grating structure are set on the top of the plastic encapsulation mold. The projection of each light-guiding structure shape corresponding to the grating structure on the packaging substrate 4 covers or partially covers one optical chip 1.
[0081] (3) Execute step S303, as Figure 7 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. 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 by fabricating the light guide structure of cutting groove 24 in the mold and then directly forming the cutting groove 24 after plastic encapsulation.
[0082] In one embodiment, the plastic encapsulation mold is placed on the packaging substrate 4 and covers the optical chip 1. The plastic encapsulation mold is made with a light guide structure shape corresponding to the light guide structure 21. A transparent plastic encapsulation material is injected into the plastic encapsulation mold for plastic encapsulation. After curing, a transparent plastic encapsulation layer 2 containing the light guide structure 21 is formed. Specifically, the process includes:
[0083] A plastic encapsulation mold is placed on the packaging substrate 4 and covers the optical chip 1. The plastic encapsulation 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. A transparent plastic encapsulation material is injected into the plastic encapsulation mold for plastic encapsulation. After curing, a transparent plastic encapsulation layer 2 including the light guide structure 21 and the cutting groove 24 is formed.
[0084] 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 sealing layer 2 and in the cutting groove 24 .
[0085] The cutting groove 24 is arranged according to the requirements of a single package. For example, if the plastic package structure of a single package includes only one optical chip 1, the cutting groove 24 is arranged between two adjacent optical chips 1. If the plastic package structure of a single package includes multiple optical chips 1, the cutting groove 24 is arranged next to the optical chip 1 located at the outermost edge of the plastic package structure. The cutting groove 24 is located at the edge of the plastic package structure after cutting.
[0086] In addition, the cutting groove 24 has a preset distance from the center line of the two adjacent optical chips 1, and all the cutting grooves 24 are close to the optical chip 1 on the same side. For example, all the cutting grooves 24 between the two adjacent optical chips 1 are close to the left optical chip 1, or all the cutting grooves 24 between the two adjacent optical chips 1 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 road 8, and the middle cutting road 8 is set along the center line of the two adjacent optical chips 1. Therefore, when cutting along the middle cutting road 8, the same side of the plastic package structure includes the cutting groove 24, and the other side does not include the cutting groove 24. Figure 10 As shown, when cutting along the middle cutting road 8 between two adjacent optical chips 1, there is no cutting groove 24 on the left side of all the plastic-encapsulated structures, while the cutting groove 24 is retained on the right side, so that light can be fed into the left side of the plastic-encapsulated structure as the light incident surface 22, and the right side of the cutting groove 24 is retained as the reflection surface 23.
[0087] Then, if Figure 8 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, etc. If the final product does not have a reflective layer 5, this step can be omitted.
[0088] (4) Execute step S304, such as Figure 9 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.
[0089] (6) Execute step S305, as Figure 10 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.
[0090] like Figure 11 As shown, the best embodiment of the present invention is an optical chip packaging method, comprising:
[0091] Step S1101, as Figure 5 As shown, chip attach and wire bonding;
[0092] Step S1102, as Figure 6 As shown, the transparent plastic sealing material is plastic-sealed, the grating is formed, and a transparent plastic sealing layer is formed after curing;
[0093] Step S1103, as Figure 7 As shown, the transparent plastic sealing layer is pre-cut to form cutting grooves;
[0094] Step S1104, as Figure 8 As shown, a metal layer is sputtered on the surface of the transparent plastic sealing layer as a reflective layer;
[0095] Step S1105, as Figure 9 As shown, an opaque plastic sealing material is used for the second plastic sealing, and an opaque plastic sealing layer is formed after curing;
[0096] Step S1106, as Figure 10 As shown, cutting and sorting are performed.
[0097] This embodiment, by fabricating the grating structure within the plastic package, provides a larger input window for external light, reduces alignment accuracy requirements, and greatly facilitates subsequent mass production. At the same time, by adding a reflective layer, incident light loss is reduced.
[0098] 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. A method for packaging an optical chip, characterized in that: include: Mounting a plurality of optical chips (1) with a light detection surface (11) provided on the top on a packaging substrate (4); A plastic encapsulation mold is placed on a packaging substrate (4) and covers the optical chip (1), wherein the plastic encapsulation mold is manufactured with a light guide structure shape corresponding to the light guide structure (21), and a transparent plastic encapsulation material is injected into the plastic encapsulation mold for plastic encapsulation, and after curing, a transparent plastic encapsulation layer (2) is formed that includes the light guide structure (21) and covers the optical chip (1); The upper surface of the transparent plastic sealing layer (2) is plastic 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), cutting the opaque plastic sealing layer (3), the transparent plastic sealing layer (2) and the packaging substrate (4) to obtain a single packaged plastic sealing structure comprising the optical chip (1), the transparent plastic sealing layer (2), the opaque plastic sealing layer (3) and the packaging substrate (4); The plastic encapsulation mold is manufactured with a plurality of light guide structure shapes corresponding to the light guide structure (21); when the plastic encapsulation mold is placed on the packaging substrate (4), each light guide structure shape corresponding to the light guide structure (21) covers one of the optical chips (1); the light guide structure (21) deflects light entering from the side light incident surface so that the light is incident on the light detection surface located on the upper surface of the optical chip; The light guide structure (21) is a grating structure, and the plastic encapsulation mold is manufactured with a light guide structure shape corresponding to the grating structure.
2. The optical chip packaging method according to claim 1, wherein: The method of plastic-sealing the upper surface of the transparent plastic-sealing layer (2) with an opaque plastic-sealing material and forming an opaque plastic-sealing layer (3) after solidification specifically comprises: Sputtering a reflective layer (5) on the upper surface of the transparent plastic sealing layer (2); The upper surface of the reflective layer (5) is sealed with an opaque sealing material, and an opaque sealing layer (3) is formed after solidification.
3. The optical chip packaging method according to claim 2, wherein: The step of sputtering a reflective layer (5) on the upper surface of the transparent plastic sealing layer (2) specifically comprises: Pre-cutting 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 sealing layer (2) and in the cutting groove (24).
4. The optical chip packaging method according to claim 2, wherein: The plastic encapsulation mold is placed on the packaging substrate (4) and covers the optical chip (1), the plastic encapsulation mold is made with a light guide structure shape corresponding to the light guide structure (21), a transparent plastic encapsulation material is injected into the plastic encapsulation mold for plastic encapsulation, and a transparent plastic encapsulation layer (2) containing the light guide structure (21) is formed after curing, specifically comprising: A plastic encapsulation mold is placed on a packaging substrate (4) and covers the optical chip (1); the plastic encapsulation mold is manufactured with a light guide structure shape corresponding to the light guide structure (21) and a cutting groove shape corresponding to the cutting groove (24); a transparent plastic encapsulation material is injected into the plastic encapsulation mold for plastic encapsulation, and after curing, a transparent plastic encapsulation layer (2) including the light guide structure (21) and the cutting groove (24) is formed; The step of sputtering a reflective layer (5) on the upper surface of the transparent plastic sealing layer (2) specifically comprises: sputtering a reflective layer (5) on the upper surface of the transparent plastic sealing layer (2) and in the cutting groove (24).
5. The optical chip packaging method according to claim 3 or 4, 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).
6. The optical chip packaging method according to claim 3 or 4, 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) are close to the optical chips (1) on the same side; The 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 packaged plastic sealing structure comprising the optical chip (1), the transparent plastic sealing layer (2), the opaque plastic sealing layer (3), and the packaging substrate (4), specifically comprising: Cutting is performed along the center line of two adjacent 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 packaged plastic sealing structure comprising the optical chip (1), the transparent plastic sealing layer (2), the opaque plastic sealing layer (3), and the packaging substrate (4).
7. The optical chip packaging method according to any one of claims 2 to 3, characterized in that: The sputtering of a reflective layer (5) specifically comprises: sputtering a layer of metal as the reflective layer (5).
8. The optical chip packaging method according to claim 7, wherein: The metal is titanium, tungsten, aluminum, gold, copper or silver.
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