Optical coupler and packaging structure of optical coupler

Abstract

An optical coupler and its packaging structure are disclosed. The packaging structure includes: a lead frame; a light-receiving chip disposed above and in contact with the lead frame; a first insulating layer disposed above and in contact with the light-receiving chip; an insulating block disposed above and in contact with the first insulating layer; a second insulating layer disposed above and in contact with the insulating block; and a light-emitting chip disposed above and in contact with the second insulating layer. At least one of the first and second insulating layers is made of a solid insulating adhesive. This solution can avoid poor wire bonding caused by the use of die-bonding adhesive, thereby preventing malfunctions of the optical coupler.

Description

Technical Field

[0001] This utility model relates to the field of chip packaging technology, and in particular to an optical coupler and an optical coupler packaging structure. Background Technology

[0002] In the application scenarios of optocouplers, in order to ensure the stability and reliability of optocouplers under specific conditions, especially in the application scenarios where optocouplers are used as switching elements, the presence of abnormalities in optocouplers is particularly important to the safety performance of the circuit.

[0003] Currently, liquid die-bonding adhesive is typically used to fix the light-emitting chip and the light-receiving chip when packaging optocouplers. However, the liquid die-bonding adhesive may flow onto the bonding pads of the light-receiving chip or the light-emitting chip, causing poor bonding or mis-conduction, which in turn leads to malfunctions in the optocoupler. Utility Model Content

[0004] The purpose of this utility model embodiment is at least to provide a packaging structure for an optocoupler that can avoid poor wire bonding caused by the use of liquid die bond adhesive, thereby preventing the optocoupler from malfunctioning.

[0005] In a first aspect, embodiments of the present invention provide a packaging structure for an optical coupler, comprising: a light-receiving chip disposed above and in contact with the lead frame; a first insulating adhesive layer disposed above and in contact with the light-receiving chip; an insulating block disposed above and in contact with the first insulating adhesive layer; a second insulating adhesive layer disposed above and in contact with the insulating block; and a light-emitting chip disposed above and in contact with the second insulating adhesive layer; wherein at least one of the first insulating adhesive layer and the second insulating adhesive layer is an insulating adhesive made of a solid material.

[0006] A first insulating layer is formed between the light-receiving chip and the insulating block using a solid insulating adhesive. And / or, a second insulating layer is formed between the light-emitting chip and the insulating block using a solid insulating adhesive. Because the first and / or second insulating layers are solid insulating adhesives, liquid die-bonding adhesive will not flow into the chip's bonding pad during the encapsulation process, thus preventing malfunctions in the optocoupler.

[0007] Optionally, the first insulating adhesive layer is disposed below the first end face of the insulating block; the projection of the first insulating adhesive layer in the vertical direction is a first projection area, the projection of the first end face of the insulating block in the vertical direction is a second projection area, and the first projection area includes the second projection area.

[0008] Optionally, the first insulating adhesive layer is made of polyimide.

[0009] Optionally, the first insulating adhesive layer is a solid polyimide adhesive, and the first insulating adhesive layer is attached between the light-receiving chip and the first end face of the insulating block.

[0010] Optionally, the second insulating adhesive layer is disposed above the second end face of the insulating block; the projection of the second insulating adhesive layer in the vertical direction is a third projection area, the projection of the second end face of the insulating block in the vertical direction is a fourth projection area, and the third projection area includes the fourth projection area.

[0011] Optionally, the material of the second insulating adhesive layer is polyimide.

[0012] Optionally, the second insulating adhesive layer is a solid polyimide adhesive, and the second insulating adhesive layer is attached between the light-receiving chip and the second end face of the insulating block.

[0013] Optionally, the material of the first insulating adhesive layer is the same as that of the second insulating adhesive layer; or, the material of the first insulating adhesive layer is different from that of the second insulating adhesive layer.

[0014] Secondly, this utility model embodiment also provides an optical coupler, including the packaging structure of any of the above-described optical couplers. Attached Figure Description

[0015] Figure 1 This is a top view of the packaging structure of an optical coupler according to an embodiment of the present invention;

[0016] Figure 2 This is a cross-sectional schematic diagram of the packaging structure of an optical coupler according to an embodiment of this utility model;

[0017] Figure 3 This is a cross-sectional schematic diagram of an existing optical coupler packaging structure. Detailed Implementation

[0018] In the prior art, an optical coupler includes a light-receiving chip and a light-emitting chip. The light-receiving chip is fixed on a lead frame. An insulating block is disposed above the light-receiving chip, and the light-emitting chip is disposed above the insulating block. The light-receiving chip and the insulating block are fixed together using liquid die-attach adhesive, and the insulating block and the light-emitting chip are also fixed together using liquid die-attach adhesive.

[0019] like Figure 3 The figure shows a cross-sectional schematic diagram of an existing optical coupler packaging structure. Figure 3In the optical coupler, the packaging structure includes a lead frame 31, a light-receiving chip 32, a first die-bonding insulating layer 33, an insulating block 34, a second die-bonding insulating layer 35, and a light-emitting chip 36. The first die-bonding insulating layer 33 and the second die-bonding insulating layer 35 are both formed by curing liquid die-bonding adhesive, and the die-bonding adhesive used for both is usually made of the same material.

[0020] However, since the packaging structure involves stacking the light-receiving chip 32, the insulating block 34, and the light-emitting chip 36, when using liquid die-bonding adhesive to fix the light-receiving chip 32 and the light-emitting chip 36, the liquid die-bonding adhesive is fluid and often flows onto the bonding pad of the chip (light-receiving chip 32, light-emitting chip 36), resulting in poor wire bonding or mis-conduction, which in turn causes the optocoupler to malfunction.

[0021] In this embodiment of the invention, a first insulating layer is formed between the light-receiving chip and the insulating block using a solid insulating adhesive. And / or, a second insulating layer is formed between the light-emitting chip and the insulating block using a solid insulating adhesive. Because the first and / or second insulating layers are solid insulating adhesives, liquid die-bonding adhesive will not flow into the chip's bonding pad during the encapsulation process, thus preventing malfunctions in the optocoupler.

[0022] To make the above-mentioned objectives, features and beneficial effects of this utility model more apparent and understandable, the specific embodiments of this utility model will be described in detail below with reference to the accompanying drawings.

[0023] This utility model provides a packaging structure for an optocoupler. (Refer to...) Figure 1 A top view of the packaging structure of the aforementioned optocoupler is given. (Refer to...) Figure 2 A cross-sectional schematic diagram of the packaging structure of the aforementioned optocoupler is provided.

[0024] The following combination Figure 1 and Figure 2 Please provide an explanation.

[0025] In this embodiment of the invention, the packaging structure of the optocoupler may include:

[0026] Lead frame 11;

[0027] The light-collecting chip 12 is disposed above the lead frame 11, and its bottom is in contact with the lead frame 11;

[0028] The first insulating adhesive layer 13 is disposed above the light-receiving chip 12 and is connected to the top of the light-receiving chip 12.

[0029] An insulating block 14 is disposed above the first insulating adhesive layer 13, and its first end face is in contact with the first insulating adhesive layer 13.

[0030] The second insulating adhesive layer 15 is disposed above the insulating block 14 and is in contact with the second end face of the insulating block 14.

[0031] The light-emitting chip 16 is disposed above and in contact with the second insulating adhesive layer 15; at least one of the first insulating adhesive layer 13 and the second insulating adhesive layer 15 is made of solid insulating adhesive.

[0032] Combination Figure 1 and Figure 2 As can be seen, in this embodiment of the utility model, in the vertical direction, the lead frame 11, the light-collecting chip 12, the first insulating adhesive layer 13, the insulating block 14, the second insulating adhesive layer 15, and the light-emitting chip 16 are stacked sequentially from bottom to top.

[0033] Specifically, the light-receiving chip 12 is placed on the lead frame 11, the first insulating layer 13 is placed on the light-receiving chip 12, the insulating block 14 is placed on the first insulating layer 13, the second insulating layer 15 is placed on the insulating block 14, and the light-emitting chip 16 is placed on the second insulating layer 15.

[0034] In a specific implementation, the lead frame 11 may include a base island functional area, and the light-receiving chip 12 may be disposed on the base island functional area. The base island functional area may be the region in the lead frame 11 that has external pins. Different lead frames 11 may have different sizes, shapes, etc., of their corresponding base island functional areas.

[0035] In practical applications, the lead frame 11 serves as the chip carrier for integrated circuits. It utilizes bonding materials (such as gold, aluminum, or copper wires) to achieve electrical connections between the internal circuit leads of the chip and external leads, forming an electrical circuit. The lead frame 11 acts as a bridge connecting the chip to external wires.

[0036] In specific implementation, the first end face and the second end face of the insulating block 14 are two horizontal end faces of the insulating block 14 in the vertical direction. The shape of the first end face and the shape of the second end face can be the same or different; the area of ​​the first end face and the area of ​​the second end face can be the same or different.

[0037] like Figure 1 and Figure 2 As shown, the first end face of the insulating block 14 is located below the second end face. The first insulating adhesive layer 13 is disposed below the first end face of the insulating block 14 and coupled to the first end face of the insulating block 14; the second insulating adhesive layer 15 is disposed above the second end face of the insulating block 14 and coupled to the second end face of the insulating block 14.

[0038] In specific implementation, the projection of the first insulating adhesive layer 13 in the vertical direction is the first projection area, and the projection of the first end face of the insulating block 14 in the vertical direction is the second projection area. The projection of the second insulating adhesive layer 15 in the vertical direction is the third projection area, and the projection of the second end face of the insulating block 14 in the vertical direction is the fourth projection area.

[0039] In practice, the area of ​​the first projection region may not be smaller than the area of ​​the second projection region. Specifically, the first projection region may include the second projection region.

[0040] The area of ​​the third projection region may be no less than the area of ​​the fourth projection region. Specifically, the third projection region may include the fourth projection region.

[0041] In this embodiment of the invention, the material of the first insulating adhesive layer 13 and the material of the second insulating adhesive layer 15 can be the same or different. By selecting the same material for the first insulating adhesive layer 13 and the second insulating adhesive layer 15, the complexity of the encapsulation process can be simplified.

[0042] In specific implementation, both the first insulating adhesive layer 13 and the second insulating adhesive layer 15 can be solid polyimide adhesive. The first insulating adhesive layer 13 can be attached between the top of the light-receiving chip 12 and the first end face of the insulating block 14 by means of adhesion, and the second insulating adhesive layer 15 can be attached between the bottom of the light-emitting chip 16 and the second end face of the insulating block 14 by means of adhesion.

[0043] In specific implementation, the first insulating adhesive layer 13 can be made of solid polyimide adhesive, the second insulating adhesive layer 15 can be made of other solid insulating adhesive materials, or the second insulating adhesive layer 15 can also be made of liquid die-bonding adhesive.

[0044] The second insulating layer 15 can be made of solid polyimide adhesive, and the first insulating layer 13 can be made of other solid insulating adhesive materials, or the first insulating layer 13 can also be made of liquid die-bonding adhesive.

[0045] In practical applications, the aforementioned liquid die-bonding adhesive possesses insulating properties. The die-bonding adhesive can be epoxy resin-based, etc.

[0046] In practical implementation, the thickness of the first insulating layer 13 and the thickness of the second insulating layer 15 can be set based on the actual application scenario and application requirements. The thickness of the first insulating layer 13 and the second insulating layer 15 should not be too large to avoid affecting the overall thickness of the packaging structure; the thickness of the first insulating layer 13 and the second insulating layer 15 should also not be too small, so as to be able to fix the light-receiving chip 12 to the first end face of the insulating block 14 and the light-emitting chip 16 to the second end face of the insulating block 14 securely.

[0047] In specific implementations, the thickness of the first insulating adhesive layer 13 can be between 0.05 mm and 0.5 mm. Specifically, a thickness value between 0.05 mm and 0.5 mm can be selected as the thickness of the first insulating adhesive layer 13.

[0048] Accordingly, the thickness of the second insulating adhesive layer 15 can be in the range of 0.05 mm to 0.5 mm. Specifically, a thickness value between 0.05 mm and 0.5 mm can be selected as the thickness of the second insulating adhesive layer 15.

[0049] In practice, the thickness of the first insulating adhesive layer 13 and the thickness of the second insulating adhesive layer 15 can be the same or different.

[0050] The production process of the packaging structure of the optocoupler provided in the above embodiments of this utility model will be described below.

[0051] Step 1), place the light-collecting chip on the lead frame.

[0052] For the lead frame, first define the base island functional area on the lead frame. Within the base island functional area, determine the region where the light-collecting chip will be placed. Then, fix the bottom of the light-collecting chip onto the lead frame.

[0053] In practical implementation, the light-receiving chip can be fixed to the lead frame using glue or adhesive. Alternatively, the light-receiving chip can also be fixed to the lead frame by soldering or other methods. This embodiment of the invention does not limit the specific implementation method of fixing the light-receiving chip to the lead frame.

[0054] Step 2) Adhere the first insulating adhesive layer to the top of the light-receiving chip.

[0055] In practice, after the light-receiving chip is fixed in place, a first insulating layer can be attached to the top of the light-receiving chip. The area of ​​the first insulating layer can be smaller than the area of ​​the top of the light-receiving chip, but equal to or slightly larger than the area of ​​the first end face of the insulating block.

[0056] In some embodiments, the first insulating adhesive layer can completely cover the first end face of the insulating block. That is, the first end face of the insulating block is completely covered by the first insulating adhesive layer.

[0057] Step 3), place the insulating block on top of the first insulating layer.

[0058] In practice, the insulating block is placed on top of the first insulating adhesive layer, and the first end face of the insulating block is in contact with the first insulating adhesive layer.

[0059] Step 4), place a second insulating layer on top of the insulating block.

[0060] In practice, a second insulating adhesive layer is attached to the second end face of the insulating block. The area of ​​the second insulating adhesive layer can be equal to or slightly larger than the area of ​​the second end face of the insulating block.

[0061] In some embodiments, the second insulating adhesive layer can completely cover the second end face of the insulating block. Alternatively, the second end face of the insulating block is completely covered by the second insulating adhesive layer.

[0062] Step 5), place the light-emitting chip on top of the second insulating adhesive layer.

[0063] In practice, after the second insulating layer is attached, a light-emitting chip is placed on top of it. Specifically, when the light-emitting chip is placed on top of the second insulating layer, the bottom of the chip is in contact with the second insulating layer.

[0064] In practice, the area of ​​the bottom of the light-emitting chip may not be greater than the area of ​​the second insulating adhesive layer.

[0065] In some embodiments, the second insulating adhesive layer can completely cover the bottom of the light-emitting chip to completely isolate the bottom of the light-emitting chip from the second end face of the insulating block.

[0066] After completing steps 1) to 5) above, the packaging structure of the optical coupler provided in the above embodiments of this utility model can be obtained.

[0067] In the above embodiments of this utility model, unless otherwise stated, "A is positioned above B" can mean that the top surface of A is in contact with the bottom surface of B.

[0068] For example, the first end face of the insulating block is located above the first insulating adhesive layer, which means that the first end face of the insulating block is in contact with the bottom surface of the first insulating adhesive layer.

[0069] In the above embodiments of this utility model, the bottom of the chip can refer to the side of the chip that has external interfaces (such as pins, pads, etc.). Correspondingly, the top of the chip is the opposite side of the chip. Those skilled in the art should understand the specific locations referred to as the bottom and top of the chip.

[0070] In practical implementation, the aforementioned light-emitting chip can be used to emit light. The light emitted by the light-emitting chip can be visible light, infrared light, etc.

[0071] In some embodiments, the light-emitting component in the light-emitting chip can be a light-emitting diode (LED), and the light-emitting chip controls the LED to emit light by outputting a driving signal to the LED.

[0072] It is understandable that the light-emitting components in a light-emitting chip can also be other types of components capable of emitting light, which will not be elaborated here.

[0073] In practical implementation, the aforementioned light-receiving chip can be used to receive the light emitted by the light-emitting chip and convert it into a corresponding electrical signal. The specific working principles and processes of the light-emitting chip and the light-receiving chip can be described with reference to the relevant content of optical couplers in the prior art.

[0074] In other words, in this embodiment of the invention, the packaging structure of the optocoupler has been improved, but the specific working principle of the optocoupler has not been changed.

[0075] In summary, in this embodiment of the invention, a first insulating layer is formed between the light-receiving chip and the insulating block using a solid insulating adhesive. And / or, a second insulating layer is formed between the light-emitting chip and the insulating block using a solid insulating adhesive. Because the first and / or second insulating layers are solid insulating adhesives, during the encapsulation process, die-bonding adhesive will not flow into the chip's bonding pad, thus preventing malfunctions in the optocoupler.

[0076] This utility model embodiment also provides an optical coupler, including the packaging structure provided in any of the above embodiments.

[0077] While the present invention has been disclosed above, it is not limited thereto. Any person skilled in the art can make various modifications and alterations without departing from the spirit and scope of the present invention; therefore, the scope of protection of the present invention should be determined by the scope defined in the claims.

Claims

1. A package structure of an optical coupler, characterized by, include: Lead frame; A light-receiving chip disposed above and in contact with the lead frame; A first insulating adhesive layer is disposed above and in contact with the light-collecting chip; An insulating block disposed above and in contact with the first insulating adhesive layer; A second insulating adhesive layer is disposed above and in contact with the insulating block; A light-emitting chip disposed above and in contact with the second insulating adhesive layer; at least one of the first insulating adhesive layer and the second insulating adhesive layer is made of a solid insulating adhesive.

2. The package structure of claim 1, wherein, The first insulating adhesive layer is disposed below the first end face of the insulating block; the projection of the first insulating adhesive layer in the vertical direction is a first projection area, the projection of the first end face of the insulating block in the vertical direction is a second projection area, and the first projection area includes the second projection area.

3. The packaging structure as described in claim 2, characterized in that, The first insulating adhesive layer is made of polyimide.

4. The packaging structure as described in claim 3, characterized in that, The first insulating adhesive layer is a solid polyimide adhesive, and the first insulating adhesive layer is attached between the light-receiving chip and the first end face of the insulating block.

5. The packaging structure as described in claim 1, characterized in that, The second insulating adhesive layer is disposed above the second end face of the insulating block; the projection of the second insulating adhesive layer in the vertical direction is a third projection area, the projection of the second end face of the insulating block in the vertical direction is a fourth projection area, and the third projection area includes the fourth projection area.

6. The packaging structure as described in claim 5, characterized in that, The second insulating layer is made of polyimide.

7. The packaging structure as described in claim 6, characterized in that, The second insulating adhesive layer is a solid polyimide adhesive, and the second insulating adhesive layer is attached between the light-receiving chip and the second end face of the insulating block.

8. The packaging structure according to any one of claims 1 to 7, characterized in that, The material of the first insulating adhesive layer is the same as that of the second insulating adhesive layer; or, the material of the first insulating adhesive layer is different from that of the second insulating adhesive layer.

9. An optical coupler, characterized in that, include: The packaging structure of the optocoupler as described in any one of claims 1 to 8.

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