Low-cost adhesive tape transfer printing method based on viscosity regulation and control

Abstract

The invention discloses a low-cost adhesive tape transfer printing method based on viscosity regulation and control. The low-cost adhesive tape transfer printing method comprises the following steps that (1) a common adhesive tape is placed at the upper end of a chip, and uniform and constant pressure is applied; (2) separating the common adhesive tape from the substrate, and picking up the chip; (3) spin-coating the thermocuring adhesive on the glass and carrying out semi-curing treatment; (4) placing a common adhesive tape at the upper end of the thermocuring adhesive, and applying uniform and constant pressure; (5) the thermocuring adhesive is heated, and the viscosity of the thermocuring adhesive is increased; (6) separating the common adhesive tape from the thermocuring adhesive, and picking up the chip from the heating part of the thermocuring adhesive; wherein the viscosity of the semi-cured thermocuring adhesive is smaller than that of a common adhesive tape and is smaller than that of the heated thermocuring adhesive. The adhesive tape has the beneficial effects that a common adhesive tape has the advantages of low cost and simple use conditions, and strict control on the use environment and operation steps is not needed, so that the operation difficulty is reduced, and the working efficiency is improved; the method can be used for global printing or patterning printing of chips.

Description

Technical Field

[0001] This invention belongs to the field of semiconductor process technology, and particularly relates to a low-cost tape transfer method based on viscosity control. Background Technology

[0002] Transfer printing is typically achieved using a transfer stamp. The strong adhesion between the stamp and the element prepared on the donor substrate picks the element off the donor substrate. After transferring it to the acceptor substrate, the adhesion between the stamp and the element is reduced, printing the element onto the acceptor substrate. Compared to traditional PDMS stamp transfer processes, tape-assisted transfer processes have advantages in transfer yield and accuracy, primarily because photosensitive tapes have a wider viscosity adjustment range than PDMS. Furthermore, PDMS stamps may deform during contact printing, leading to transfer accuracy issues, while tape does not have this problem.

[0003] Chinese patent document CN111868192A discloses an adhesive tape and a method for manufacturing a semiconductor device, particularly reducing transfer defects when manufacturing tiny semiconductor chips using a pre-cutting method, specifically reducing transfer defects when transferring the chip 21 from the back-abrasion tape 10 to the pick-up tape 30 or adhesive tape. This improves the transfer efficiency of transferring the chip from the back-abrasion tape 10 to the pick-up tape 30 or adhesive tape. As a solution, the present invention provides an adhesive tape 10, characterized in that it is preferably used as the aforementioned back-abrasion tape, comprising a substrate 11 and an adhesive layer 12 disposed on one side of the substrate 11. The adhesive layer 12 is composed of an energy-curable adhesive. After attaching a silicon wafer mirror to the adhesive layer 12, the adhesive layer is cured by irradiating it with energy rays, and further cured under a pressure of 0.5 N / cm. 2 The adhesion at 23°C after hot pressing for 5 seconds at 210°C is less than 9.0 N / 25 mm.

[0004] The aforementioned patented solution uses back-abrasion tape and adhesive tape for transfer, utilizing two tapes with different adhesive properties to peel off the chip. In order to reduce the transfer defect rate and ensure the chip adhesion effect, the manufacturing methods and usage steps of the back-abrasion tape and adhesive tape are relatively complex, and the temperature in the operation steps also needs to be strictly controlled. This also results in problems such as high transfer cost and low operation efficiency. Summary of the Invention

[0005] To overcome the limitations of existing technologies, such as low precision of transfer stamps and complex and costly transfer tape steps, which make it difficult to achieve patterned transfer of chips at low cost, one objective of this invention is to provide a low-cost tape transfer method based on viscosity control. This method utilizes the viscosity changes between ordinary tape and thermosetting adhesive to selectively transfer chips from ordinary tape to thermosetting adhesive, thereby achieving patterned transfer of chips at low cost.

[0006] To achieve the above objectives, the present invention employs the following technical solution: a low-cost adhesive tape transfer method based on viscosity control, comprising the following steps:

[0007] (1) Place ordinary tape on the top of the chip array on the substrate and apply uniform and constant pressure;

[0008] (2) The ordinary tape is separated from the substrate, and the chip is picked up by the ordinary tape;

[0009] (3) The thermosetting adhesive is spin-coated onto the glass and then semi-cured;

[0010] (4) Place the chip picked up by the ordinary tape on the top of the thermosetting adhesive and apply uniform and constant pressure;

[0011] (5) Heating the thermosetting adhesive increases its viscosity;

[0012] (6) Separate the ordinary tape from the thermosetting adhesive, wherein the heated portion of the thermosetting adhesive picks up the chip on the ordinary tape;

[0013] The adhesive strength of the semi-cured thermosetting adhesive is less than that of the ordinary tape, which is less than the adhesive strength of the thermosetting adhesive after heating.

[0014] Optionally, the heating method in step (5) is global heating, which means that the chip can be printed globally, thereby improving printing efficiency.

[0015] Optionally, the heating method in step (5) is local heating, which can pattern the chip to achieve high-precision printing, thereby enabling chips of different sizes and types to be printed on the same substrate.

[0016] Furthermore, the local heating is laser selective heating. After the irradiated part of the thermosetting adhesive is heated, its adhesion is further enhanced to a level greater than that of the ordinary tape. After the ordinary tape is removed, the chip facing the irradiated part is transferred onto the thermosetting adhesive, thereby completing selective printing.

[0017] Furthermore, the semi-curing process involves holding the glass coated with the thermosetting adhesive at a first temperature for a certain period of time; the first temperature is lower than the heating temperature in step (5).

[0018] Preferably, the ordinary tape has mobile adhesiveness, which allows it to remain sticky during use while being easily removed without leaving any residue.

[0019] Specifically, the ordinary tape is masking tape, fiber tape, or PVC tape.

[0020] Preferably, the thermosetting adhesive is solid after semi-curing treatment, and the chip will not slip after being placed on the thermosetting adhesive, thereby improving printing accuracy.

[0021] Specifically, the thermosetting adhesive is polydimethylsiloxane, Ecoflex, or silicone rubber.

[0022] Compared with the prior art, the beneficial effects of the present invention are as follows: it utilizes the difference in adhesion between ordinary tape and thermosetting adhesive for transfer printing. Ordinary tape has the advantages of low cost and simple use conditions, and does not require strict control of the use environment and operation steps, thereby reducing the difficulty of operation and improving work efficiency; it can be used for global printing or patterned printing of chips. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the process of picking up chips on a substrate according to the present invention;

[0024] Figure 2 This is a schematic diagram of the chip transfer process of the present invention.

[0025] In the diagram: 1. Substrate; 2. Chip; 3. Ordinary tape; 4. Glass; 5. Thermosetting adhesive; 6. Heating. Detailed Implementation

[0026] The present invention will now be further described in conjunction with the accompanying drawings and specific embodiments. It should be noted that, without conflict, the various embodiments or technical features described below can be arbitrarily combined to form new embodiments.

[0027] In the description of this invention, it should be noted that the directional terms such as "center", "lateral", "longitudinal", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", and "counterclockwise" indicate the orientation and positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. They should not be construed as limiting the specific protection scope of this invention.

[0028] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features. Thus, the use of "first" and "second" to define a feature may explicitly or implicitly include one or more of that feature, and in the description of this invention, "a number" means two or more, unless otherwise explicitly specified.

[0029] In this invention, unless otherwise explicitly specified and limited, terms such as "set" and "install" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can also refer to a mechanical connection; they can refer to a direct connection or a connection through an intermediate medium; or they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0030] See Figure 1 A tightly packed chip 2 is grown on a substrate 1, with the chip 2 on top and the substrate 1 below. Ordinary adhesive tape 3 is placed on top of the chip 2, adhering to the chip 2 and applying uniform and constant pressure. Figure 1 b) Separate the ordinary adhesive tape 3 from the substrate 1. The ordinary adhesive tape 3 has a certain degree of stickiness. At this time, the chip 2 is picked up by the ordinary adhesive tape 3. Figure 1 c).

[0031] See Figure 2 The thermosetting adhesive 5 is spin-coated onto glass 4. The chip 2, picked up by the ordinary tape 3, is brought close to the semi-cured thermosetting adhesive 5, and a fixing pressure is applied. Figure 2 a) The thermosetting adhesive 5 is spin-coated onto the glass 4 and subjected to a semi-curing treatment. The semi-cured thermosetting adhesive 5 is solid. The pressed whole or part is then heated 6 ( Figure 2 b) The adhesiveness of the heated thermosetting adhesive 5 increases. The ordinary tape 3 is separated from the thermosetting adhesive 5, and the heated portion of the thermosetting adhesive 5 picks up the chip 2 from the ordinary tape 3, completing the selective printing process of the chip 2.

[0032] The ordinary adhesive tape 3 has mobile adhesive properties and can be masking tape, fiber tape, PVC tape, etc. It maintains its adhesiveness during use and can be easily removed without leaving residue. The adhesiveness of the mobile adhesive tape is reversible; that is, the adhesiveness weakens when the tape is stretched or moved, and strengthens when compressed or stationary. This characteristic allows the mobile adhesive tape to adapt well to objects of different shapes and surfaces during the transfer process, while avoiding the residue and damage that may be left by traditional tapes during the transfer process. The advantage of mobile adhesiveness in transfer tape is that it enables a high-precision, high-efficiency, low-cost, and highly integrated transfer process, while avoiding many of the disadvantages of traditional transfer technologies.

[0033] The thermosetting adhesive 5 is solid in its semi-cured state, and its viscosity gradually increases with continued heating. The thermosetting adhesive 5 can be polydimethylsiloxane, Ecoflex, silicone rubber, etc.

[0034] The above description is only a specific embodiment of the present invention, but the technical features of the present invention are not limited thereto. Any changes or modifications made by those skilled in the art within the scope of the present invention are covered by the patent scope of the present invention.

Claims

1. A low-cost tape transfer method based on viscosity control, characterized in that: Includes the following steps: (1) Place ordinary tape on the top of the chip array on the substrate and apply uniform and constant pressure; (2) The ordinary tape is separated from the substrate, and the chip is picked up by the ordinary tape; (3) The thermosetting adhesive is spin-coated onto the glass and then semi-cured; (4) Place the chip picked up by the ordinary tape on the top of the thermosetting adhesive and apply uniform and constant pressure; (5) Heating the thermosetting adhesive increases its viscosity; (6) Separate the ordinary tape from the thermosetting adhesive, wherein the heated portion of the thermosetting adhesive picks up the chip on the ordinary tape; The adhesive strength of the semi-cured thermosetting adhesive is less than that of the ordinary tape, which is less than the adhesive strength of the thermosetting adhesive after heating.

2. The transfer method as described in claim 1, characterized in that: The heating method in step (5) is global heating.

3. The transfer method as described in claim 1, characterized in that: The heating method in step (5) is local heating.

4. The transfer method as described in claim 3, characterized in that: The localized heating is laser selective heating.

5. The transfer method as described in claims 1-4, characterized in that: The semi-curing process involves holding the glass coated with the thermosetting adhesive at a first temperature for a certain period of time; the first temperature is lower than the heating temperature in step (5).

6. The transfer method according to any one of claims 1-4, characterized in that: The ordinary tape has mobile adhesive properties.

7. The transfer method as described in claim 6, characterized in that: The ordinary tape is masking tape, fiber tape, or PVC tape.

8. The transfer method according to any one of claims 1-4, characterized in that: The thermosetting adhesive becomes solid after semi-curing.

9. The transfer method as described in claim 8, characterized in that: The thermosetting adhesive is polydimethylsiloxane, Ecoflex, or silicone rubber.

10. The transfer method as described in claim 5, characterized in that: The ordinary tape has mobile adhesive properties.

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