MEMS Device Anti-Electromagnetic Crosstalk Packaging Process

Abstract

The present invention discloses a packaging process for preventing electromagnetic crosstalk of MEMS devices, which makes the product have higher integration, smaller packaging size and better warpage control. For the product obtained by the process of the present invention, the electromagnetic interference prevention layer is integrated in the black light-shielding material, and the space occupied by the product packaging layer is small, so that the designed size of the product is small and thin; the process of the present invention adopts the wafer-level packaging method, the whole process flow is easy to control, and the UPH is high; the chip of the product obtained by the process of the present invention is completely encapsulated by the glue solution, so the reliability and stability of the product are high.

Description

Technical Field

[0001] The present invention relates to the technical field of wafer-level packaging of chips, and in particular to a packaging process for preventing electromagnetic crosstalk of MEMS devices. This technology is suitable for terminal devices such as smart phones, wearable devices, tablet computers, and laptop computers. Background Art

[0002] The growing demand for high performance, miniaturization, and portability of devices such as optoelectronic sensors and radio frequency electronic devices has made it inevitable to operate multiple high-performance devices at different frequencies in a limited area. This increases the possibility of electromagnetic interference (EMI) problems within the system. Traditional EMI shielding covers have proven to be too bulky, expensive, take up too much space, and are generally inefficient for today's packaging technologies.

[0003] Therefore, there is an urgent need to develop wafer-level packaging process technologies integrated with EMI layers. Summary of the Invention

[0004] To solve the above technical problems, the present invention designs a packaging process for preventing electromagnetic crosstalk of MEMS devices, making the product have higher integration, smaller packaging size, and better warpage control.

[0005] The present invention adopts the following technical solutions:

[0006] A packaging process for preventing electromagnetic crosstalk of MEMS devices, the process steps are as follows:

[0007] S1. Preparation of glass carrier: The glass carrier is subjected to double-sided polishing treatment, and a double-sided tape is pasted on the upper surface of the glass carrier;

[0008] S2. Bonding and fixing of PCB board: A customized PCB board transfer machine is used to bond and fix the PCB board with chips to the double-sided tape;

[0009] S3. Assembly of electromagnetic interference prevention layer: According to the requirements of the product structure design, a customized electromagnetic interference prevention sheet is assembled onto the PCB;

[0010] S4. Spraying of transparent epoxy resin glue in working mold: A working mold is selected. The working mold is recessed with a glue injection groove covering the chips on the entire PCB board. The glue injection port of the working mold communicates with the glue injection groove. Convex platforms are respectively arranged in the glue injection groove corresponding to the chips. The transparent epoxy resin glue is dispensed onto the convex platforms by spraying or dispensing;

[0011] S5. Alignment and assembly of working mold: A wafer automatic alignment device is used to align and assemble the working mold that has been injected with transparent epoxy resin glue with the PCB board fixed on the glass carrier into a set, and a UV lamp is used to irradiate to pre-cure the transparent epoxy resin glue;

[0012] S6, Glue injection and curing: Use a fully automatic wafer glue injection machine to inject black epoxy resin glue into the cavity of the glue injection groove through the preset glue injection port of the working mold, and cure the black epoxy resin glue by combining ultraviolet irradiation and baking to form a wafer;

[0013] S7, Wafer demolding: Use an automatic demolding machine to separate the working mold from the wafer;

[0014] S8, Glass carrier disassembly: Use an automatic cutting machine to perform trench cutting on the surface of the wafer to release the internal stress generated during thermal curing in the wafer, and then disassemble the wafer from the glass carrier;

[0015] S9, Component cutting: Use a fully automatic wafer cutting machine to cut and separate the wafer to obtain a MEMS device with electromagnetic crosstalk prevention packaging.

[0016] Preferably, in step S1, the glass carrier is double-sided polished to a TTV of less than or equal to 20 microns.

[0017] Preferably, the chips on the PCB board are arranged uniformly in an array.

[0018] Preferably, in step S3, the electromagnetic interference prevention sheet is assembled onto the outer edge of the chip on the PCB board to cover the chip.

[0019] Preferably, in step S4, the depth of the glue injection groove recessed in the working mold is coordinated with the height of the chip as required.

[0020] Preferably, in step S4, the glue injection port of the working mold is set at the central position of the working mold.

[0021] Preferably, in step S9, the obtained MEMS device with electromagnetic crosstalk prevention packaging includes a black shielding layer, a light-transmitting layer, a PCB board, a chip, and an electromagnetic interference prevention sheet. The black shielding layer surrounds and covers the outer edge of the chip. The black shielding layer and the chip are respectively fixed on the PCB board. Light-transmitting layers are respectively installed outside the chip. The outer edge of the light-transmitting layer is also surrounded and covered by the black shielding layer and clamped tightly outside the chip. The electromagnetic interference prevention sheet is embedded in the black shielding layer and covers the outer edge of the chip in a circle.

[0022] Preferably, in step S4, the boss is frustum-shaped.

[0023] The beneficial effects of the present invention are: (1) For the product obtained by the process of the present invention, the electromagnetic interference prevention layer is integrated in the black light-blocking material, and the packaging layer of the product occupies less space, so that the product design size is smaller and thinner; (2) The process of the present invention adopts a wafer-level packaging method, and the entire process flow is easy to control, and the UPH is relatively high; (3) The chips of the product obtained by the process of the present invention are completely wrapped and encapsulated by the glue, so the reliability and stability of the product are relatively high. Description of the Drawings

[0024] Figure 1 It is a schematic structural diagram of preparing and pasting a double-sided tape on a glass carrier in double-sided polishing treatment in the present invention;

[0025] Figure 2 It is Figure 1 a schematic structural diagram of bonding a PCB board with a chip on the double-sided tape in;

[0026] Figure 3 It is Figure 2 a schematic structural diagram of assembling a customized electromagnetic interference prevention sheet on the outer edge of the chip in;

[0027] Figure 4 It is a schematic structural diagram of dispensing glue on a convex platform in the working mold of the present invention;

[0028] Figure 5 It is Figure 3 a schematic structural diagram of the alignment and assembly of the structure in and the working mold;

[0029] Figure 6 It is Figure 5 a schematic structural diagram of injecting black epoxy resin glue liquid into the glue injection port in the present invention;

[0030] Figure 7 It is Figure 6 a schematic structural diagram after demolding;

[0031] Figure 8 It is Figure 7 a schematic structural diagram of making trench cutting on the wafer structure in;

[0032] Figure 9 It is Figure 8 a schematic structural diagram of the wafer structure in;

[0033] Figure 10 It is Figure 9 a schematic structural diagram after the wafer structure is cut and separated in;

[0034] Figure 11 It is a schematic structural diagram of a MEMS device with electromagnetic interference prevention encapsulated and formed by the process of the present invention;

[0035] In the figure: 1. Glass carrier, 2. Double-sided tape, 3. PCB board, 4. Electromagnetic interference prevention sheet, 5. Working mold, 6. Glue injection port, 7. Glue injection groove, 8. Convex platform, 9. Transparent epoxy resin glue liquid, 10. Black epoxy resin glue liquid, 11. Trench, 12. Chip, 13. Black shielding layer, 14. Light-transmitting layer. Detailed implementation manners

[0036] The technical solution of the present invention will be further specifically described below through specific embodiments in conjunction with the accompanying drawings:

[0037] Embodiment: A packaging process for preventing electromagnetic crosstalk of MEMS devices, and the process steps are as follows:

[0038] S1. Preparation of glass carrier: The glass carrier 1 is subjected to double-sided polishing treatment, and a double-sided adhesive tape 2 is pasted on the upper surface of the glass carrier, as Figure 1 shown;

[0039] S2. Bonding and fixing of PCB board: Use a customized PCB board transfer machine to bond and fix the PCB board 3 with chips to the double-sided adhesive tape, as Figure 2 shown;

[0040] S3. Assembly of electromagnetic interference prevention layer: According to the requirements of the product structure design, customize an electromagnetic interference prevention sheet 4 and assemble it onto the PCB, as Figure 3 shown;

[0041] S4. Spraying of transparent epoxy resin glue on the working mold: Select a working mold 5. The working mold is recessed with a glue injection groove 7 covering the chips on the entire PCB board. The glue injection port 6 of the working mold communicates with the glue injection groove. Corresponding to the chips in the glue injection groove, there are convex platforms 8 respectively. The transparent epoxy resin glue is dispensed onto the convex platforms by spraying or dispensing, as Figure 4 shown;

[0042] S5. Alignment and assembly of the working mold: Use a wafer automatic alignment device to align and assemble the working mold injected with transparent epoxy resin glue 9 with the PCB board fixed on the glass carrier into a set, and use a UV lamp to irradiate to pre-cure the transparent epoxy resin glue, as Figure 5 shown;

[0043] S6. Glue injection and curing: Use a fully automatic wafer glue injection machine to inject black epoxy resin glue 10 into the cavity of the glue injection groove through the preset glue injection port of the working mold, and use a combination of ultraviolet irradiation and baking to cure the black epoxy resin glue to form a wafer, as Figure 6 shown;

[0044] S7. Wafer demolding: Use an automatic demolding machine to separate the working mold from the wafer, as Figure 7 shown;

[0045] S8. Disassembly of glass carrier: Use an automatic cutting machine to cut a trench 11 on the surface of the wafer to release the internal stress generated during thermal curing in the wafer, and then disassemble the wafer from the glass carrier, as Figure 8 and Figure 9 shown;

[0046] S9. Element cutting: Use a fully automatic wafer cutting machine to cut and separate the wafer,Figure 10 as shown in; obtain the MEMS device with electromagnetic crosstalk prevention packaging, such as Figure 11 shown in.

[0047] In step S1, the double-sided polishing treatment of the glass carrier is carried out until the TTV is less than or equal to 20 microns.

[0048] The chips on the PCB board are arranged evenly in an array.

[0049] In step S3, the electromagnetic interference prevention sheet is assembled onto the outer edge of the chip on the PCB board to cover the chip.

[0050] In step S4, the depth of the glue injection groove recessed in the working mold is matched with the height of the chip as required.

[0051] In step S4, the glue injection port of the working mold is arranged at the central position of the working mold.

[0052] In step S9, the obtained MEMS device with electromagnetic crosstalk prevention packaging includes a black shielding layer 13, a light-transmitting layer 14, a PCB board, a chip 12, and an electromagnetic interference prevention sheet. The black shielding layer surrounds and covers the outer edge of the chip. The black shielding layer and the chip are respectively fixed on the PCB board. The light-transmitting layers are respectively installed outside the chip. The outer edge of the light-transmitting layer is also surrounded and covered by the black shielding layer and clamped outside the chip. The electromagnetic interference prevention sheet is embedded in the black shielding layer, and the electromagnetic interference prevention sheet covers the outer edge of the chip in a circle.

[0053] In step S4, the boss is frustum-shaped.

[0054] The above-described embodiments are only a preferred solution of the present invention, and do not impose any form of limitation on the present invention. There are other variations and modifications without exceeding the technical solutions recorded in the claims.

Claims

1. A packaging process for preventing electromagnetic crosstalk of MEMS devices, characterized in that, The process steps are as follows: S1. Glass carrier preparation: The glass carrier is polished on both sides, and a double-sided tape is pasted on the upper surface of the glass carrier; S2. PCB board bonding and fixing: Use a customized PCB board transplanting machine to bond and fix the PCB board with chips to the double-sided tape; S3. Assembly of the electromagnetic interference prevention layer: According to the requirements of the product structure design, customize an electromagnetic interference prevention sheet and assemble it onto the PCB; S4. Spraying of transparent glue solution on the working mold: Select a working mold. The working mold is recessed with a glue injection groove that covers the chips on the entire PCB board. The glue injection port of the working mold is connected to the glue injection groove. Convex platforms are respectively arranged in the glue injection groove corresponding to the chips. The transparent epoxy resin glue solution is dropped onto the convex platforms by spraying or dispensing; S5. Alignment and assembly of the working mold: Use a wafer automatic alignment device to align and assemble the working mold that has been injected with transparent epoxy resin glue solution with the PCB board fixed on the glass carrier into a set, and use a UV lamp to irradiate to pre-cure the transparent epoxy resin glue solution; S6. Glue injection and curing: Use a fully automatic wafer glue injection machine to inject black epoxy resin glue solution into the cavity of the glue injection groove through the preset glue injection port of the working mold, and use a combination of ultraviolet irradiation and baking to cure the black epoxy resin glue solution to form a wafer; S7. Wafer demolding: Use an automatic demolding machine to separate the working mold from the wafer; S8. Disassembly of the glass carrier: Use an automatic cutting machine to make trench cuts on the surface of the wafer to release the internal stress generated during thermal curing in the wafer, and then disassemble the wafer from the glass carrier; S9. Component cutting: Use a fully automatic wafer cutting machine to cut and separate the wafer to obtain a MEMS device with electromagnetic crosstalk prevention packaging.

2. The MEMS device electromagnetic crosstalk prevention packaging process according to claim 1, characterized in that, In step S1, the glass carrier is polished on both sides until the TTV is less than or equal to 20 microns.

3. The MEMS device electromagnetic crosstalk prevention packaging process according to claim 1, characterized in that The chips on the PCB board are evenly arranged in an array.

4. The MEMS device electromagnetic crosstalk prevention packaging process according to claim 1, characterized in that, In step S3, the electromagnetic interference prevention sheet is assembled onto the outer edge of the chips on the PCB board to cover the chips.

5. The MEMS device electromagnetic crosstalk prevention packaging process according to claim 1, characterized in that, In step S4, the depth of the glue injection groove recessed in the working mold is matched with the height of the chips as required.

6. The MEMS device electromagnetic crosstalk prevention packaging process according to claim 1, characterized in that, In step S4, the glue injection port of the working mold is arranged at the center position of the working mold.

7. The MEMS device electromagnetic crosstalk prevention packaging process according to claim 1, characterized in that, In step S9, the obtained MEMS device with electromagnetic crosstalk prevention packaging includes a black shielding layer, a light-transmitting layer, a PCB board, chips, and an electromagnetic interference prevention sheet. The black shielding layer surrounds and covers the outer edge of the chips. The black shielding layer and the chips are respectively fixed on the PCB board. Light-transmitting layers are respectively installed outside the chips. The outer edge of the light-transmitting layer is also surrounded and covered by the black shielding layer and clamped outside the chips. The electromagnetic interference prevention sheet is embedded in the black shielding layer and covers the outer edge of the chips in a circle.

8. The MEMS device electromagnetic crosstalk prevention packaging process according to claim 1, characterized in that, In step S4, the convex platform is in the shape of a frustum of a cone.

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