CN112477391B - Magnetron transfer stamp and transfer method based on bistable structure - Google Patents

Abstract

The invention discloses a magnetic control transfer printing stamp based on a bistable structure and a transfer printing method, wherein the stamp is of a two-dimensional structure and comprises a stamp main body with a cavity array, a bistable structure magnetic film and an adhesion block arranged at the bottom of the bistable structure magnetic film; the transfer printing method comprises the following steps: 1) when picking up, the seal is pressed on the element/substrate, and the element is picked up from the donor substrate by using the viscosity of the seal/element interface; 2) during printing, under the continuous action of an external magnetic field, the bistable structure magnetic film on the stamp deforms and jumps downwards to generate impact force and deformation extrusion force on the element, so that the element is separated from the stamp and is printed on a receiver substrate. The seal has simple structure and low cost; the response speed is high; non-contact transfer printing can be realized at normal temperature and in a vacuum environment; has stronger pick-up and printing performance; the method can realize high-efficiency global transfer printing and accurate patterning transfer printing by changing the action range of the magnetic field.

Description

Magnetron transfer stamp and transfer method based on bistable structure

technical field

The invention relates to a transfer printing technology, in particular to a magnetron transfer stamp based on a bistable structure and a transfer method, which can be used for the transfer printing of any patterned electronic components.

Background technique

Transfer transfer technology is a versatile material assembly technique that transfers a large number of discretely fabricated electronic components from a traditional rigid substrate (donor substrate) to another non-traditional (e.g., flexible) via a soft polymer stamp. or stretchable) on the receiving substrate (acceptor substrate), so as to form a two-dimensional or three-dimensional spatially ordered integrated array (see Luo Hongyu, Linghu Changhong, Song Jizhou. The transfer printing of stretchable and flexible inorganic electronic devices Review of Mechanics Research [J]. Science in China: Physics, Mechanics and Astronomy, 2018, v.48(09):134-148.). Because the polymer stamp is easy to make, low in cost, high in transfer efficiency and has a wide range of transferable materials, it is often used in the integration and preparation of various electronic devices. Such as thin-film solar cells (thin-film solar cells), flexible capacitors (flexible capacitors), light-emitting diodes (LEDs), flexible electrodes, flexible display screens, etc. are all assembled by transfer printing technology.

Generally, the process of transfer technology is divided into two steps of picking and printing. Picking components from a donor substrate requires stronger adhesion at the stamp/component interface than component/substrate adhesion, and printing components onto a recipient substrate requires weaker adhesion between the stamp/component than component/substrate adhesion between. Therefore, regulating the interfacial adhesion of stamps/components is the key to realize transfer pick-up and printing.

Existing transfer printing technologies, such as rate-dependent transfer technology (Meitl M, Zhu Z, Kumar V, et al. Transfer printing by kinetic control of adhesion to an elastomeric stamp [J]. Nature Materials, 2006, 5(1) :33-38.), surface relief transfer technology (Kim S, Wu J, Carlson A, et al. Microstructured elastomeric surfaces with reversible adhesion and examples of their use in deterministic assembly by transfer printing [J]. Proceedings of the National Academy of Sciences, 2010, 107(40): 17095-17100.), Shear-enhanced adhesiveless transfer printing for use in deterministic materials assembly[J ].AppliedPhysics Letters,2011.), Laser thermal mismatch transfer printing technology (Li R,Li Y,LüC,et al.Thermo-mechanical modeling of laser-driven non-contact transfer printing:two-dimensional analysis[J]. Soft Matter, 2012, 8(27): 7122-7127.) and area regulation transfer technology (Carlson A, Wang S, Elvikis P, et al. Active, programmable elastomeric surfaces with tunable adhesion for deterministic assembly by transfer printing[J] .Advanced Functional Materials, 2012, 22(21): 4476-4484.) etc. all achieve transfer by adjusting the interfacial adhesion between the stamp and the element.

However, these methods all reduce the interface adhesion between the stamp and the component by reducing the interface adhesion strength, which is affected by factors such as material parameters, separation speed, pre-pressure, contact area, etc., and the control range is limited. The components under the strong interfacial adhesion of the stamp cannot be released directly, which limits its application range.

SUMMARY OF THE INVENTION

Aiming at the deficiencies of the existing transfer technology, the present invention proposes a magnetron transfer stamp and transfer method based on a bistable structure. This structure can provide stronger release properties, allowing the stamp to release elements from strongly adhered interfaces. The transfer seal is assembled from top to bottom by the seal body, the bistable structure magnetic film and the adhesive block arranged at the bottom of the bistable structure magnetic film, and the seal is a two-dimensional seal; the The stamp body is provided with an array of cavities running through its bottom to provide deformation space for the bistable structure magnetic film; the fixed end of the bistable structure magnetic film is fixed by the seal body and the adhesive block.

The specific transfer method is as follows: 1) When picking up, press the stamp on the surface of the element, and use the adhesive block on the stamp and the interface adhesion between the element to pick up the element; 2) During printing, move the stamp to the acceptor substrate. Above, a magnetic field is applied to the bistable magnetic film on the seal to make the film deform and jump downwards, generating impact force and deformation squeezing force on the surface of the element, so that the element overcomes the interfacial adhesion force between the element and the seal, and completes the non-contact print.

In addition to the above pick-up method, the magnetic film of the bistable structure that pops up can also be used to exert a deformation and squeezing force on the surface of the component to offset the adhesive force of the adhesive block on the stamp to the component, and the adhesive force that is not offset by the adhesive force can be offset. The area can pick up components, enabling a selective pick-up process.

In addition to the above-mentioned non-contact printing methods, the stamp with components can also be pressed on the surface of the acceptor substrate during printing to realize contact printing and improve the accuracy of the printing position and the printing success rate.

In addition to the above-mentioned printing method in which the magnetic field continues to act, the magnetic film can be deformed and jumped by the momentary switch of the magnetic field during printing, and the impact force and deformation pressing force are applied to the components to realize the release of the components. The rapid switching of the magnetic field improves operational safety and reduces energy consumption.

The applied magnetic field can be globally driven or locally driven, and large-scale and high-efficiency transfer can be achieved under global driving; programmable patterned transfer can be achieved under local driving.

The main body of the stamp can be selected from non-magnetic materials that are easy to process and have high modulus, such as polymer materials such as PDMS (polydimethylsiloxane), non-magnetic metal materials or acrylic and other polymer materials. During the printing process, the main body of the seal will not be greatly deformed, and the non-magnetism ensures that the main body of the seal will not be affected by the magnetic field.

The bistable structure magnetic film can be made of high modulus and strong magnetic metal materials such as iron foil. The high modulus and strong magnetic properties allow the film to exert high impact and deformation squeezing force on the element, which can significantly improve the printing ability of the stamp. Or use a hybrid material formed by polymer and magnetic particles. The modulus of the bistable structure magnetic film is at least GPa level, and its magnetic requirement is that the magnetic force received by the bistable structure magnetic film can make it jump and flip under the action of a magnetic field.

The adhesive block can be of single-layer or double-layer structure, such as PDMS, SMP and other easy-to-prepare sticky polymer single-layer structure, and double-layer structure composed of low-modulus base material and adhesive material such as tape. The single-layer or double-layer structure is to ensure that the stamp adhesive block can have a strong adhesion and pick-up force to the components.

Preferably, in order to facilitate the preparation of the stamp, PDMS (polydimethylsiloxane) can be selected as both the main material of the stamp and the material of the stamp adhering block. By adjusting the ratio of PDMS body and curing agent reasonably, the modulus of PDMS can be adjusted to reduce the deformation of the stamp body during the transfer process and enhance the adhesion force when the adhesive block is picked up.

Preferably, in order to improve the printing performance, the bistable magnetic thin film material can be selected as iron foil.

The beneficial effects of the invention are as follows: the stamp has a simple structure and low cost; the printing response time is fast and the printing efficiency is high; the non-contact transfer printing can be realized under normal temperature or vacuum; it has stronger pick-up and printing performance; It can achieve both efficient global transfer and precise pattern transfer.

Description of drawings

FIG. 1 is a schematic structural diagram of the minimum unit of the magnetron transfer stamp based on the bistable structure proposed by the present invention.

FIG. 2 is a transfer principle diagram of the magnetron transfer stamp based on the bistable structure proposed by the present invention.

FIG. 3 is a flow chart of contact printing based on the magnetron transfer stamp based on the bistable structure proposed by the present invention.

FIG. 4 is a flow chart of applying a transient magnetic field to the magnetron transfer stamp based on the bistable structure proposed by the present invention for printing.

5 is a flow chart of applying a global magnetic field to a magnetron transfer stamp based on a bistable structure proposed by the present invention to realize large-scale non-contact transfer.

FIG. 6 is a flow chart of applying a local magnetic field to a magnetron transfer stamp based on a bistable structure to realize programmable selective pickup according to the present invention.

7 is a flow chart of applying a local magnetic field to a magnetron transfer stamp based on a bistable structure to realize programmable patterned non-contact printing proposed by the present invention.

In the figure: 1-stamp body 2-non-jump-deformed bistable structure magnetic film 3-jump-deformed bistable structure magnetic film 4-adhesion block 5-element 6-donor substrate 7-acceptor substrate 8- vertical downward magnetic field

Detailed ways

The content of the present invention is further described below in conjunction with the accompanying drawings and embodiments.

As an example, but not limiting the scope of the present invention, FIG. 1 is a schematic structural diagram of the smallest unit of the magnetron transfer stamp based on the bistable structure of the present invention. The material of the seal body 1 is PDMS prepared with a square cavity array (the ratio of curing agent and body is 1:10); the bistable structure magnetic film is made of iron foil metal material; the adhesive on the fixed end surface of the bistable structure magnetic film is The material of block 4 is PDMS with a ratio of curing agent to body of 1:10; these structures together form a complete transfer stamp.

As an example, but not limiting the scope of the present invention, FIG. 2 is a transfer principle diagram of the magnetron transfer stamp based on the bistable structure proposed in the present invention. Fig. 2 a-c: Picking up components with an adhesive block. d-f in Fig. 2: In the continuously acting vertical downward magnetic field 8, the magnetic film of the bistable structure deforms and jumps, and the printed element.

First move the stamp over the element 5 on the donor substrate 6 ( FIG. 2 a ), move down to make the adhesive block 4 contact the element 5 ( FIG. 2 b ), and use the stickiness of the adhesive block 4 to remove the element 5 from the donor substrate 6 Peel off (Figure 2c), enabling the pick-up process.

Then, transfer the stamp with the element 5 to the top of the acceptor substrate 7, keep a distance from the acceptor substrate 7, and continuously apply a vertical downward magnetic field 8 (Fig. The state-structured magnetic film 3 produces an impact force and a deformation squeezing force on the element 5, and the element 5 is printed from the stamp to the receiver substrate 7 (Fig. 2e), and finally the stamp is withdrawn to realize the non-contact printing process (Fig. 2f) .

As an example, but not limiting the scope of the present invention, FIG. 3 is a flow chart of contact printing based on a magnetron transfer stamp with a bistable structure proposed by the present invention. First move the stamp over the element 5 on the donor substrate 6 (FIG. 3a), move down to make the adhesive block 4 contact the element (FIG. 3b), and use the stickiness of the adhesive block 4 to peel the element 5 from the donor substrate 6 (Fig. 3c), the pick-up process is realized. Then, transfer the stamp with the element 5 to the top of the acceptor substrate 7, contact with the acceptor substrate 7, and continuously apply a vertical downward magnetic field 8 (Fig. 3d), so that the bistable structure deforms and jumps due to the magnetic force. The magnetic film 3 produces an impact force and a deformation pressing force on the element 5, and the element 5 is printed from the stamp onto the receiver substrate 7 (Fig. 3e), and finally the stamp is withdrawn to realize the contact printing process (Fig. 3f).

As an example, but not limiting the scope of the present invention, FIG. 4 is a flow chart of applying a transient magnetic field to a magnetron transfer stamp based on the bistable structure proposed by the present invention for printing. First, move the stamp over the element 5 on the donor substrate 6 (Fig. 4a), move it downward to make the adhesive block 4 contact the element 5 (Fig. 4b), and use the stickiness of the adhesive block 4 to remove the element 5 from the donor substrate 6. Peel off (Fig. 4c), enabling the pick-up process. Then, the stamp with the element 5 is transferred to the top of the acceptor substrate 7, in contact with the acceptor substrate 7, and the vertical downward magnetic field 8 is applied and closed in a short time (Fig. 4d), so that the deformation jumps due to the magnetic force. The bistable structure of the magnetic film 3 produces an impact force and a deformation squeezing force on the element 5, and the element 5 is printed from the seal to the receiver substrate 7 (Fig. 4e), and finally the seal is withdrawn to realize the contact printing process (Fig. 4e). 4f).

As an example, but not limiting the scope of the present invention, FIG. 5 is a flow chart of applying a global magnetic field to a magnetron transfer stamp based on a bistable structure proposed by the present invention to realize large-scale non-contact transfer. The pickup process (a-b in Figure 5) and printing process (c-d in Figure 5) are the same as those in Figure 2, except that the entire transfer process uses a large-scale global magnetic field to pick up and print devices on a large scale to improve the transfer efficiency.

As an example, but not limiting the scope of the present invention, FIG. 6 is a flowchart of applying a local magnetic field to a magnetron transfer stamp based on a bistable structure proposed by the present invention to achieve programmable selective pickup. First, a vertical downward magnetic field 8 is applied to the non-jump-deformed bistable structure magnetic film 2 in the designated area of the seal (Fig. 6a), so that the non-jump-deformed bistable structure magnetic film 2 is deformed and jumped, and the In the non-adhered state (Fig. 6b), the stamp is then pressed onto the element 5 placed on the donor substrate 6, and the bistable structure magnetic film 3, which has been jumped and deformed, is deformed by pressing against the element 5 (Fig. 6c); then upward Moving the stamp, except for the non-adhered area, components 5 at the remaining positions were successfully selectively picked up (Fig. 6d).

As an example, but not limiting the scope of the present invention, FIG. 7 is a flowchart of applying a local magnetic field to a magnetron transfer stamp based on a bistable structure proposed by the present invention to realize programmable patterned non-contact printing. The stamp is first pressed onto the element 5 on the donor substrate 6 ( FIG. 7 a ), and the element 5 is peeled off from the donor substrate 6 by the stickiness of the adhesive block 4 ( FIG. 7 b ) to realize the pick-up process. The stamp with the element 5 is transferred over the receiver substrate 7, at a distance from the receiver substrate 7, and then a local vertically downward magnetic field 8 is continuously applied to the printing area (Fig. 7c). The magnetic film of the bistable structure in the printing area is deformed and jumped, which generates an impact force and a deformation pressing force on the element 5 in the area, and pushes the element 5 from the stamp to realize the non-contact selective printing process (Fig. 7d).

Claims (10)

1. A magnetic control transfer seal based on a bistable structure is characterized by being formed by sequentially assembling a seal main body, a bistable structure magnetic film and an adhesive block arranged at the bottom of the bistable structure magnetic film from top to bottom; the seal body is provided with a cavity array penetrating through the bottom of the seal body; the fixing end of the bistable structure magnetic film is fixed by the seal main body and the adhesion block in an attaching mode, and the bistable structure magnetic film is in contact with an element after being deformed.

2. The magnetic control transfer stamp based on the bistable structure of claim 1, wherein the stamp body material is a nonmagnetic polymer, a nonmagnetic metal or an acrylic material.

3. The bistable-structure-based magnetically controlled transfer stamp of claim 1, wherein said adhesion blocks are of a single-layer or double-layer structure with adhesion.

4. The magnetron transfer printing stamp based on the bistable structure according to claim 1, wherein the material of the bistable structure magnetic thin film is a magnetic metal material or a mixed material formed by high polymer and magnetic particles, and the modulus of the bistable structure magnetic thin film is at least in the GPa level.

5. The magnetic control transfer stamp based on the bistable structure according to claim 1, wherein the stamp body material and the adhesive block material are both polydimethylsiloxane, and the content of the curing agent in the stamp body material is equal to or higher than that in the adhesive block material.

6. The magnetic control transfer stamp based on the bistable structure according to claim 4, wherein the bistable structure magnetic film is made of iron foil material.

7. A large-scale programmable transfer method, characterized in that, realized based on the stamp according to any one of claims 1 to 6, the steps are as follows:

when picking up, the seal is pressed on the component/substrate, and the component is picked up from the donor substrate by using the viscosity of the adhesive block;

during printing, under the continuous action of the magnetic field, the bistable structure magnetic film on the stamp deforms and jumps downwards to generate impact force and deformation extrusion force on the element, so that the element is separated from the stamp and is printed on a receiver substrate.

8. The large-scale programmable transfer printing method according to claim 7, wherein the external drive is a global magnetic field, and the stamp is driven to realize large-scale transfer printing; the external drive is a local magnetic field, and the stamp is driven to realize programmable patterned transfer printing.

9. The mass programmable transfer method according to claim 7, wherein the picking up is: a magnetic field is applied to a designated position of the stamp, the corresponding bistable structure magnetic film deforms and jumps, the release configuration is maintained, so that the corresponding position is kept in an adhesion-free state, when the stamp is in contact with an element on a donor substrate, the element except the position in the adhesion-free state can be picked up, and programmable selective pickup is realized.

10. The mass programmable transfer method of claim 7, wherein the printing is by: and applying a transient magnetic field to the designated position of the stamp to drive the bistable structure magnetic film to deform and jump, and generating impact force and deformation extrusion force on the element to separate the element from the stamp and print the element on a receiver substrate.

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