Chip transfer printing and mounting process method

Abstract

The invention provides a chip transfer printing and mounting process method. The method comprises the following steps of: arranging and pasting chips on an adhesive film in a whole column; pasting a UV (Ultraviolet) film on one surface of the chip opposite to the adhesive film; removing the adhesive film from the chip pasted with the UV film; a CDF film is attached to the position, where the adhesive film is removed, of the chip, and the chip is pressed into the CDF film; removing the UV film from the chip pasted with the CDF film; and stripping the CDF film at the bottom of the chip from the surrounding CDF film, and bonding the chip with the CDF film at the bottom with the substrate. According to the chip transfer printing chip mounting process method, the chip mounting quality is good, the chip mounting efficiency is high, and the chip mounting cost is low.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor technology, and particularly relates to a chip transfer and mounting process method. Background Art

[0002] In the semiconductor industry, an ultra-small chip refers to a chip with a size between 0.25*0.25 mm and 0.1*0.1 mm. A conductive material is required for electrical conduction connection between the bottom of the chip mounted on the substrate and the substrate.

[0003] Currently, the ultra-small chip mounting process flow includes viscous film chip incoming material, dotting mounting glue, picking up the chip, and placing the chip. During mounting, the mounting glue dotted on the substrate will wrap around the periphery of the chip and bond the chip to the substrate. Due to the small size of the chip, it is difficult to control the consistency of the dotting amount of the mounting glue, and the mounting glue has a certain buoyancy, which easily causes problems such as the mounting glue overflowing onto the chip surface or the chip tilting due to the buoyancy of the mounting glue, affecting the mounting quality.

[0004] To avoid problems such as the mounting glue overflowing onto the chip surface or the chip tilting due to the buoyancy of the mounting glue, some enterprises also use the inverted film mounting process for ultra-small chip mounting. That is, first, the ultra-small chips arranged in a whole row are inverted and molded on the CDF film, then the CDF films between the bottoms of each chip are cut, and then each chip with the CDF film at the bottom is picked up by a suction nozzle and bonded to the substrate. This inverted mold mounting process does not require dotting mounting glue on the substrate, and problems such as the mounting glue overflowing onto the chip surface or the chip tilting will not occur. However, when dividing the CDF films at the bottoms of each chip, due to the too small size of the chip, a large number of chips are likely to fly off. Moreover, the most widely used cutting machines in the industry are the cutting equipment of internationally well-known brands DISCO and TSK. The price of a single cutting machine is usually more than 1 million yuan, and the price of a single cutting blade is also 300 yuan. Therefore, adopting this inverted mold mounting process has problems such as high cost, low mounting quality, and low mounting efficiency.

[0005] Therefore, there is an urgent need for an ultra-small size chip transfer and mounting process method with high mounting quality, high mounting effect, and low mounting cost. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to provide a chip transfer and mounting process method with good mounting quality, high mounting efficiency, and low mounting cost.

[0007] To solve the above technical problem, the present invention provides a chip transfer and mounting process method, which is applicable to the transfer and mounting of ultra-small size chips with a size between 0.25*0.25 mm and 0.1*0.1 mm. The method includes the following steps:

[0008] Arrange the chips in an array and attach them to the adhesive film:

[0009] Attach a UV film to one side of the chip opposite to the adhesive film;

[0010] Remove the adhesive film from the chip with the UV film attached;

[0011] Attach a CDF film to the position on the chip where the adhesive film has been removed, and press the chip into the CDF film;

[0012] Remove the UV film from the chip with the CDF film attached;

[0013] Peel off the CDF film at the bottom of the chip from the surrounding CDF film, and bond the chip with the CDF film at the bottom to the substrate.

[0014] Further, the step of attaching the UV film to the chip includes: attaching the UV film to the chip under the condition that the temperature is 20°C - 30°C.

[0015] Further, the step of removing the adhesive film from the chip includes: first place the chip in a vacuum adsorption heating platform and heat it under the condition that the temperature is 60°C - 80°C, and then remove the adhesive film on the chip.

[0016] Further, the step of attaching the CDF film to the chip includes: invert the chip on the film laminating machine, set the CDF film on the chip, and press the bottom of the chip into the CDF film by 5 - 10 μm through the pressure of the roller.

[0017] Further, the chemical composition of the CDF film includes, by mass percentage, 80% - 85% of silver and 15% - 20% of resin glue.

[0018] Further, the thickness of the CDF film is 14 - 16 μm.

[0019] Further, the pressure for the roller to press the chip into the CDF film is controlled to be 3 - 4 kg.

[0020] Further, the step of removing the UV film from the chip includes: place the chip in an ultraviolet light irradiator, the irradiation time is 25 - 35 s, and then remove the UV film from the chip.

[0021] Further, the step of peeling off the CDF film at the bottom of the chip from the surrounding CDF film and bonding the chip with the CDF film at the bottom to the substrate includes:

[0022] Use a thimble to peel off the CDF film at the bottom of the chip from the surrounding CDF film;

[0023] Use a suction nozzle to pick up the chip with the CDF film at the bottom and bond it to the substrate.

[0024] Further, the step of sucking the chip with a CDF film at the bottom and bonding it to the substrate with a suction nozzle includes: sucking the chip with the suction nozzle and placing it on the substrate, and applying a downward pressure to the chip, so that the chip is bonded to the substrate through the CDF film at the bottom of the chip.

[0025] Further, the downward pressure applied by the suction nozzle is 100-300 g.

[0026] A chip transfer and mounting process method provided by the present invention adopts an inverted film mounting process. First, a whole row of ultra-small chips are inverted on a CDF film, and a roller is used to roll and press to make the chips press into the CDF film to a certain depth. Then, a thimble is used to push the chips upward from the bottom of the chips, so that the CDF film at the bottom of the chips is peeled off from the surrounding CDF film. Then, a suction nozzle is used to suck the chips with a CDF film at the bottom, and the chips are bonded to the substrate through the CDF film at the bottom of the chips. This mounting process method not only does not require dropping mounting glue on the substrate, and there will be no mounting quality problems such as the mounting glue overflowing onto the chip surface or the chip tilting. Moreover, before picking up each chip with the suction nozzle, it is not necessary to divide the CDF film at the bottom of each chip, which not only avoids the problem that ultra-small chips are prone to fly off during the CDF film cutting process, but also saves the investment in cutting equipment, consumables, labor, and dispensing consumables, greatly saving costs and improving economic benefits. Each production line can save more than 1 million yuan. Description of the Drawings

[0027] Figure 1 It is a schematic structural diagram of the whole row of chips arranged and pasted on the viscous film in the chip transfer and mounting process method provided by the embodiment of the present invention;

[0028] Figure 2 It is a schematic structural diagram of the whole chip with a viscous film inverted and pasted on the UV film in the chip transfer and mounting process method provided by the embodiment of the present invention;

[0029] Figure 3 It is a schematic structural diagram of the chip without the viscous film in the chip transfer and mounting process method provided by the embodiment of the present invention;

[0030] Figure 4 It is a schematic structural diagram when pasting a CDF film on the chip in the chip transfer and mounting process method provided by the embodiment of the present invention;

[0031] Figure 5 It is a schematic structural diagram of the chip after pasting the CDF film in the chip transfer and mounting process method provided by the embodiment of the present invention;

[0032] Figure 6 It is a schematic structural diagram of the chip pressed into the CDF film to a certain depth in the chip transfer and mounting process method provided by the embodiment of the present invention;

[0033] Figure 7Schematic diagram of the structure for removing the UV film from the chip in the chip transfer and mounting process method provided by the embodiment of the present invention;

[0034] Figure 8 Schematic diagram of the structure of the chip after pasting the CDF being picked up in the chip transfer and mounting process method provided by the embodiment of the present invention;

[0035] Figure 9 Product effect diagram of the chip transfer and mounting process method provided by the embodiment of the present invention applied to the ultra-small chip packaging of the client. Detailed implementation manners

[0036] Refer to Figure 1 A chip transfer and mounting process method provided by the embodiment of the present invention is applicable to the transfer and mounting of ultra-small chips with sizes between 0.25 * 0.25 mm and 0.1 * 0.1 mm, and it includes the following steps:

[0037] Step 1) Refer to Figure 1 , arrange the chips in an array and paste them on the sticky film. Among them, the incoming chips are good chips obtained through sorting. The sticky film is a kind of film with stickiness, and the stickiness of the sticky film will be greatly reduced when heated. Through the sticky film, the incoming chips can be stuck in an array to facilitate the subsequent film pasting operation.

[0038] Step 2) Refer to Figure 2 , paste a UV film on the side of the chip opposite to the sticky film, that is, invert and paste the whole chip with the sticky film on the UV film.

[0039] Among them, in order to avoid damaging the UV film due to excessive temperature, pasting the UV film on the chip is completed under the temperature condition of 20°C - 30°C.

[0040] Among them, the UV film is a kind of ultraviolet film with strong stickiness before ultraviolet light irradiation and weak stickiness after ultraviolet light irradiation, which can facilitate inverting and sticking the whole chip with the sticky film on the UV film.

[0041] As a specific implementation manner of the present invention, the UV film selected is the UV film with the model of Nitto 3102d.

[0042] Step 3) Refer to Figure 3 , heat the chip with the UV film to remove the sticky film.

[0043] Among them, when removing the sticky film from the chip, the chip with the sticky film is moved to the vacuum adsorption heating platform for heating. In order to make the temperature of the sticky film rise and the stickiness decrease so that it is easy to remove from the chip, and at the same time not to damage the UV film on the chip due to excessive temperature, the heating temperature on the vacuum adsorption heating platform is controlled at 60 - 80°C, and then the sticky film on the chip is directly removed by peeling.

[0044] As a specific embodiment of the present invention, the optimal temperature for heating the de-sticking film is 70 °C.

[0045] Step 4) Refer to Figure 4 , and stick a CDF film at the position where the de-sticking film is removed on the chip. After the chip is stuck with the CDF film, it is as Figure 5 shown.

[0046] Among them, sticking the CDF film on the chip means moving the chip to a film sticking machine, covering the CDF film on the chip, and in order to facilitate the subsequent peeling of the CDF film at the bottom of each chip from the surrounding CDF film, a roller is used to press the chip into the CDF film to a certain depth by rolling on the CDF film on the chip, as Figure 6 shown.

[0047] As a specific embodiment of the present invention, the film sticking machine is specifically selected as the NITTO MSA300PII film sticking machine.

[0048] Among them, the CDF film selected is the CDF film with the model CDF315 provided by Loctite. In order to achieve a better bonding effect between the chip and the substrate, the CDF film with a thickness of 14 - 16 μm is selected.

[0049] As a specific embodiment of the present invention, the thickness of the CDF film is preferably 15 μm.

[0050] Among them, the chemical composition of the CDF film is, by mass percentage, 80% - 85% silver and 15% - 20% resin glue. The CDF film is a sticky chip bonding conductive film product with excellent properties such as high thermal conductivity, high electrical conductivity, high reliability, and excellent overflow glue control.

[0051] As a specific embodiment of the present invention, since the thickness of the CDF film is 14 - 16 μm, in order to easily peel the CDF film at the bottom of each chip from the surrounding CDF film without reducing the strength of the CDF film bonding the chip and the substrate, the depth of the chip pressed into the CDF film is preferably 5 - 10 μm.

[0052] In order to press the chip into the CDF film to the above depth, the rolling pressure applied by the roller on the CDF film of the chip is controlled at 3 - 4 kg.

[0053] Step 5) Remove the UV film from the chip with the CDF film by ultraviolet light irradiation. The chip with the CDF film after removing the UV film is as Figure 7 shown.

[0054] Among them, when removing the UV film on the chip, the chip is placed in an ultraviolet light irradiation machine. After irradiating for 25 - 35 s, the viscosity of the UV film decreases, and thus the UV film can be peeled off from the chip.

[0055] As a specific embodiment of the present invention, the ultraviolet light irradiator selected is the Lintec RAD2010M12 ultraviolet light irradiator.

[0056] As an optimal embodiment of the present invention, the UV film can be removed after the chip is irradiated for 30 s.

[0057] Step 6) Refer to Figure 8 , on the chip mounter, select the ejector pin and the nozzle that match the chip size, and complete the picking up of the chip and bonding the chip to the substrate.

[0058] Among them, the picking up and placing of the chip are completed on the chip mounter. Specifically, the ASM 8312 chip mounter is selected.

[0059] First, use the ejector pin that matches the chip size to jack up the chip from the bottom of the chip, so that the CDF film at the bottom of the chip is peeled off from the surrounding CDF film. Then, use the nozzle to suck up the chip with the CDF film at the bottom. After the nozzle sucks up the chip, place the chip on the substrate and apply a downward pressure to the substrate, so that the chip is bonded to the substrate through the CDF film at its bottom.

[0060] Among them, the downward pressure applied by the nozzle to the chip is 100 - 300 g.

[0061] Since the CDF film is only 15 μm thick and the CDF film has a certain flexibility, after the rolling operation with a roller with a pressure of 3 - 4 kg, the chip will be squeezed into the CDF film by 5 - 10 microns, so that a pre-cutting effect is formed around the CDF film at the bottom of the chip. In this way, it is easy to peel off the CDF film at the bottom of each chip from the CDF film around the bottom of the chip that is not subjected to positive extrusion. When a force is applied upward from the bottom of the chip with the ejector pin, the CDF film at the bottom of the chip can be peeled off from the surrounding CDF film, thus obtaining a chip with a CDF film at the bottom.

[0062] The chip with a CDF film at the bottom is sucked up by the nozzle, and then the nozzle applies a downward pressure of 100 - 300 g to place the chip on the substrate. The chip is bonded to the substrate through the CDF film at the bottom, thus completing the transfer and mounting of the ultra-small size chip.

[0063] A chip transfer and mounting process method provided by the present invention adopts an inverted film mounting process. First, a whole row of ultra-small chips are inverted on a CDF film, and a roller is used to roll and press the chips into the CDF film to a certain depth, which is equivalent to forming a pre-cutting effect between the CDF film at the bottom of the chip and the CDF film around the bottom of the chip. In this way, the CDF film at the bottom of the chip and the CDF film around the chip that is not subjected to positive extrusion are easily peeled off. Then, a thimble can easily lift the chip upward from the bottom of the chip, so that the CDF film at the bottom of the chip is peeled off from the surrounding CDF film. Then, a suction nozzle is used to pick up the chip with the CDF film at the bottom, and the chip can be adhered to the substrate by applying a downward pressure through the CDF film at the bottom of the chip. Before picking up each chip with the suction nozzle, this mounting process method does not require dividing the CDF film at the bottom of each chip, which not only avoids the problem that ultra-small chips are easily bounced off during the CDF film cutting process, but also saves the investment in cutting equipment, consumables, labor, and dispensing consumables, greatly saving costs and improving economic benefits. The funds saved can reach more than 1 million yuan.

[0064] See Figure 9 , applying the chip transfer and mounting process method provided by the present invention to the packaging of ultra-small chip products of the client. The ultra-small chips with a size of 0.20 * 0.20 mm are transferred and mounted on a substrate of a flexible printed circuit board (FPC). The mounting effect can reach the expected effect, and the product lighting and electrical testing are all normal.

[0065] Finally, it should be noted that the above specific implementation manners are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to the examples, those of ordinary skill in the art should understand that the technical solutions of the present invention can be modified or equivalently replaced without departing from the spirit and scope of the technical solutions of the present invention, and they should all be covered by the scope of the claims of the present invention.

Claims

1. A chip transfer and mounting process method, characterized in that, it includes the following steps: Arrange the chips in an array and stick them on the adhesive film: Stick a UV film on one side of the chips opposite to the adhesive film; Remove the adhesive film from the chips with the UV film stuck; Stick a CDF film at the position where the adhesive film is removed from the chips, and press the chips into the CDF film; Remove the UV film from the chips with the CDF film stuck; Peel off the CDF film at the bottom of the chips from the surrounding CDF film, and bond the chips with the CDF film at the bottom to the substrate.

2. The chip transfer and mounting process method according to claim 1, characterized in that, the step of sticking the UV film on the chips includes: sticking the UV film on the chips under the condition that the temperature is 20°C - 30°C.

3. The chip transfer and mounting process method according to claim 1, characterized in that, the step of removing the adhesive film from the chips includes: first place the chips on a vacuum adsorption heating platform and heat them under the condition that the temperature is 60°C - 80°C, and then remove the adhesive film on the chips.

4. The chip transfer and mounting process method according to claim 1, characterized in that, the step of sticking the CDF film on the chips includes: invert the chips on a film laminating machine, set the CDF film on the chips, and press the chips into the CDF film by 5 - 10 μm through the pressure of the roller.

5. The chip transfer and mounting process method according to claim 4, characterized in that: the chemical composition of the CDF film, by mass percentage, includes 80% - 85% of silver and 15% - 20% of resin glue.

6. The chip transfer and mounting process method according to claim 5, characterized in that: the thickness of the CDF film is 14 - 16 μm.

7. The chip transfer and mounting process method according to claim 1, characterized in that: the pressure for the roller to press the chips into the CDF film is controlled to be 3 - 4 kg.

8. The chip transfer and mounting process method according to claim 1, characterized in that, the step of removing the UV film from the chips includes: place the chips in an ultraviolet light irradiator, irradiate for 25 - 35 s, and then remove the UV film from the chips.

9. The chip transfer and mounting process method according to claim 1, characterized in that, the step of peeling off the CDF film at the bottom of the chips from the surrounding CDF film and bonding the chips with the CDF film at the bottom to the substrate includes: Use a thimble to peel off the CDF film at the bottom of the chips from the surrounding CDF film; Use a suction nozzle to pick up the chips with the CDF film at the bottom and bond them to the substrate.

10. The chip transfer and mounting process method according to claim 9, characterized in that, the step of using a suction nozzle to pick up the chips with the CDF film at the bottom and bond them to the substrate includes: use a suction nozzle to pick up the chips and place them on the substrate, and apply a downward pressure to the chips, and bond the chips to the substrate through the CDF film at the bottom of the chips.

11. The chip transfer and mounting process method according to claim 10, characterized in that, the downward pressure applied by the suction nozzle is 100 - 300 g.

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