Packaging process for fan-out packaging and product

Abstract

The invention discloses a packaging process for fan-out packaging and a product, and belongs to the technical field of semiconductor processing. A magnetic temporary bonding pad is applied to a temporary bonding layer at an I / O position of a chip and a temporary bonding layer on a carrier respectively, so that the chip is automatically aligned and fixed at a specified position, and the chip is not driven to move due to liquidation and flowing of a plastic package material under high temperature and high pressure of plastic package in a subsequent process; according to the invention, the automatic alignment of the chip is realized through the magnetic temporary bonding pad on the chip and the carrier so as to ensure the precision; and the material has two curing agents with different temperatures, so that the chip can be fixed on the temporary bonding pad of the carrier, and the displacement during plastic packaging is avoided.

Description

Technical Field

[0001] The present invention belongs to the technical field of semiconductor processing, and in particular relates to a packaging process and product for fan-out packaging. Background Art

[0002] Fan-Out Packaging is an advanced microelectronic packaging technology that allows additional input / output points (I / O points) to be formed in the area extended outside the chip, thereby increasing packaging density and reducing package size. This technology aims to overcome the limitations of traditional packaging technology in terms of high performance and miniaturization.

[0003] The current industry practice is as follows:

[0004] (1) Use a higher precision placement machine or even a smaller precision. The disadvantage is that the high-precision equipment is expensive, and the equipment running speed must be reduced to provide placement accuracy, so the throughput is low;

[0005] (2) To prevent further chip displacement caused by the plastic encapsulation process after chip mounting, a temporary bonding layer is provided to enhance chip adhesion. The disadvantage is that the adhesive layer of the bonding layer remains on the chip surface and IO, and needs to be removed in the post-process.

[0006] (3) Use AOI equipment to measure the position of each chip and use the subsequent pattern transfer process to compensate the circuits of all units of each chip. The disadvantage is that the compensation has a limit. If the chip displacement exceeds a certain range, the unit must be scrapped. If the chip displacement exceeds a certain range, the circuit changes too much and affects the electrical performance of the original equipment.

[0007] Therefore, there are still some defects in the current industry practices. Summary of the invention

[0008] In view of the above situation, in order to overcome the defects of the prior art, the present invention provides a packaging process and product for fan-out packaging, wherein the packaging process comprises the following steps:

[0009] S1. Print temporary bonding pads on the wafer and the carrier, and heat and semi-cure them under a magnetic field, so as to make the magnetic powders have the same direction under the magnetic field, and fix the direction of the magnetic powders by curing, so as to form the effect of magnetic attraction and automatic alignment when the chip is mounted, and then cut the wafer into single chips;

[0010] S2, using a laminating machine to laminate the temporary bonding layer onto the carrier for carrying a subsequent temporary bonding pad, and printing the temporary bonding pad onto the temporary bonding layer;

[0011] S3, during semi-curing, placing under a magnetic field and applying a leveling process to make the temporary bonding pad into a flat COIN;

[0012] S4, the magnetic powder positioning of the temporary bonding pad on the wafer is opposite to the magnetic powder positioning of the temporary bonding pad on the wear body, so that the N and S poles attract each other during the patching to complete the automatic positioning;

[0013] S5, performing final curing after mounting the chip, and performing the process under vacuum pressing;

[0014] S6, performing plastic sealing, and removing the carrier and the temporary bonding layer;

[0015] S7, removing the temporary bonding pads on the wafer and the carrier with a solvent to expose the metal pads of the chip;

[0016] S8. Perform the known fan-out process.

[0017] Furthermore, the temporary bonding pad includes magnetic powder and a two-component curing agent.

[0018] Furthermore, one of the two types of curing agents has a curing temperature of less than 100° C., and the curing agent is semi-cured in S1.

[0019] Furthermore, the curing temperature of the other one of the two types of curing agents is less than 150° C., which is lower than the foaming temperature of the temporary bonding layer, and the curing agent is finally cured in S5.

[0020] Further, the S6 may adopt one of the following two methods:

[0021] (1) separating the carrier from the temporary bonding layer by heating, and then removing the temporary bonding layer by using a film peeling machine;

[0022] (2) The plastic package body and the temporary bonding layer are separated by heating, and then the temporary bonding layer on the carrier is removed by a film peeling machine to recover the carrier.

[0023] The beneficial effects of the present invention are:

[0024] (1) The present invention applies a temporary bonding pad with magnetic properties to the chip I / O and the temporary bonding layer on the carrier respectively to automatically align the chip and fix it at a specified position so as not to be displaced by the liquefied flow of the plastic sealing material under high temperature and high pressure in the subsequent plastic sealing process;

[0025] (2) The present invention realizes automatic chip alignment by means of temporary magnetic bonding pads on the chip and the carrier to ensure accuracy, and the material has two different temperature curing agents to fix the chip on the temporary bonding pad of the carrier and avoid displacement during plastic packaging. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 A process flow chart of a packaging process and product for fan-out packaging of the present invention;

[0027] Figure 2 is a schematic diagram of the structure of a temporary bonding pad;

[0028] FIG3 is a schematic diagram of the process flow of the present invention;

[0029] Figure 4 It is a schematic diagram of the fan-out structure of a chip in the prior art.

[0030] The accompanying drawings are used to provide further understanding of the present invention and constitute a part of the specification. They are used to explain the present invention together with the embodiments of the present invention and do not constitute a limitation of the present invention.

[0031] legend:

[0032] 1. Temporary bonding pad; 2. Magnetic powder; 3. Wafer; 4. Chip; 5. Carrier; 6. Temporary bonding layer; 7. Plastic package; 8. Chip substrate; 9. Metal pad; 10. PI layer; 11. Passivation layer. DETAILED DESCRIPTION

[0033] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0034] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments.

[0035] Example 1

[0036] A packaging process and product for fan-out packaging

[0037] The packaging process comprises the following steps:

[0038] S1, printing a temporary bonding pad 1 (including magnetic powder 2 and a two-component curing agent) on the wafer 3 and the carrier 5, see Figure 2 , and heat semi-curing (first dose) under a magnetic field, the purpose is to make the direction of the magnetic powder 2 consistent under the magnetic field, and the direction of the magnetic powder 2 is fixed by high-temperature curing, the purpose is to form a magnetic attraction automatic alignment effect when the chip 4 is mounted, and then the wafer 3 is cut into single chips 4, see Figure 3A , 3BThe two-component curing agent has two-component curing agent, one with a curing temperature of <100 degrees, and the other with a curing temperature of <150 degrees, which is lower than the foaming temperature of the temporary bonding layer 6, so that the temporary bonding layer 6 does not foam during the high-temperature curing process in step S1, and further, in order to remove the carrier 5 and the temporary bonding layer 6 in step S6, the high temperature causes the temporary bonding layer 6 to foam, thereby separating the temporary bonding layer 6 from the carrier 5 or the temporary bonding layer 6 from the plastic package 7. The function of the temporary bonding pad 1 is to automatically align in step S5 and achieve the effect of the wafer surface being covered after plastic packaging in step S6;

[0039] S2, using a laminating machine to laminate the temporary bonding layer 6 onto the carrier 5 for carrying the subsequent temporary bonding pad 1, and printing the temporary bonding pad 1 onto the temporary bonding layer 6, Figure 3C ;

[0040] S3, during semi-curing, placing the temporary bonding pad 1 under a magnetic field and applying a leveling process to make the temporary bonding pad 1 into a flat COIN;

[0041] S4, the magnetic powder 2 of the temporary bonding pad 1 on the wafer 3 is positioned opposite to the magnetic powder 2 of the temporary bonding pad 1 on the carrier 5, so that the N and S poles attract each other during the patching process to complete the automatic positioning, see Figure 3D ;

[0042] S5, after mounting the chip 4, perform final curing (second dose) under vacuum pressing;

[0043] S6, plastic sealing is performed, and the carrier 5 and the temporary bonding layer 6 are removed. Figure 3E , adopt the following method: separate the carrier 5 and the temporary bonding layer 6 by high temperature heating to produce foaming phenomenon, thereby separating the carrier 5 and the temporary bonding layer 6, and then remove the temporary bonding layer 6 by a film peeling machine;

[0044] S7, using a solvent to remove the temporary bonding pads 1 on the wafer 3 and the carrier 5, exposing the metal pads 9 of the chip 4, wherein the chip 4 further includes a chip substrate 8, a PI layer 10, and a passivation layer 11, Figure 3F ;

[0045] S8. Perform the known fan-out process.

[0046] Example 2

[0047] A packaging process and product for fan-out packaging

[0048] The difference between this embodiment and embodiment 1 is that the step of S6 is different, and the remaining steps are the same as those of embodiment 1.

[0049] The step S6 is: perform plastic encapsulation, remove the carrier 5 and the temporary bonding layer 6, Figure 3E , the following method is adopted: the plastic package body 7 and the temporary bonding layer 6 are separated by high-temperature heating to produce foaming phenomenon, and then the temporary bonding layer 6 on the carrier 5 is removed by the film tearing machine to recover the carrier 5.

[0050] The difference between Example 2 and Example 1 in the method of removing the temporary bonding layer 6 in step S6 depends on whether the foaming layer of the bonding layer 6 is combined with the carrier 5 or the plastic packaging body 7. In Example 1, the foaming layer of the bonding layer 6 is combined with the carrier 5, and in Example 2, the foaming layer of the bonding layer 6 is combined with the plastic packaging body 7.

[0051] The present invention forms a hexagonal chip encapsulation structure, thereby solving the problem of bonding strength between different materials in the traditional technology.

[0052] See Figure 4 Different from the chip fan-out structure in the prior art (five-sided encapsulation, the front of the chip is encapsulated by ABF or PI layer), the chip hexagonal encapsulation structure formed by the present invention can effectively eliminate the problem of interface bonding strength between ABF / PI and plastic encapsulation material.

[0053] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

[0054] The present invention and its implementation methods are described above, which is not restrictive. The drawings are only one of the implementation methods of the present invention, and the actual application is not limited thereto. In short, if ordinary technicians in the field are inspired by it and design methods and embodiments similar to the technical solution without creativity without departing from the purpose of the invention, they should all fall within the protection scope of the present invention.

Claims

1. A packaging process for fan-out packaging, characterized in that: The packaging process comprises the following steps: S1. Print temporary bonding pads on the wafer and the carrier, and heat and semi-cure them under a magnetic field, so as to make the magnetic powders have the same direction under the magnetic field, and fix the direction of the magnetic powders by curing, so as to form the effect of magnetic attraction and automatic alignment when the chip is mounted, and then cut the wafer into single chips; S2, using a laminating machine to laminate the temporary bonding layer onto the carrier for carrying a subsequent temporary bonding pad, and printing the temporary bonding pad onto the temporary bonding layer; S3, during semi-curing, placing under a magnetic field and applying a leveling process to make the temporary bonding pad into a flat COIN; S4, the magnetic powder positioning of the temporary bonding pad on the wafer is opposite to the magnetic powder positioning of the temporary bonding pad on the body, so that the N and S poles attract each other during the patching to complete the automatic positioning; S5, performing final curing after mounting the chip, and performing the process under vacuum pressing; S6, performing plastic sealing, and removing the carrier and the temporary bonding layer; S7, removing the temporary bonding pads on the wafer and the carrier with a solvent to expose the metal pads of the chip; S8. Perform the known fan-out process.

2. A packaging process for fan-out packaging according to claim 1, characterized in that: The temporary bonding pad comprises magnetic powder and a two-component curing agent.

3. A packaging process for fan-out packaging according to claim 2, characterized in that: The curing temperature of one of the two-component curing agent is less than 100° C., and the curing agent is semi-cured in S1.

4. A packaging process for fan-out packaging according to claim 3, characterized in that: The curing temperature of the other one of the two types of curing agents is less than 150° C., which is lower than the foaming temperature of the temporary bonding layer. The curing agent is finally cured in S5 .

5. A packaging process for fan-out packaging according to claim 4, characterized in that: The S6 adopts one of the following two methods: (1) separating the carrier from the temporary bonding layer by heating, and then removing the temporary bonding layer by using a film peeling machine; (2) The plastic package body and the temporary bonding layer are separated by heating, and then the temporary bonding layer on the carrier is removed by a film peeling machine to recover the carrier.

6. A packaging product for fan-out packaging, characterized in that: Prepared according to the packaging process described in claims 1-5.

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