CN113433062B - Method and device for testing joint force between stamp unit and sample - Google Patents

Abstract

The present application provides a method and device for testing the bonding force between a stamp unit and a sample. The test method includes: manufacturing a flexible film, wherein the design parameters of the flexible film of the stamp unit are obtained by a design method of the stamp unit, manufacturing a flexible film with bonding posts; assembling the flexible film and a sample, wherein the flexible film is assembled to the air cavity. an upper jig, which mounts the sample to the lower jig and opposes the engagement post; and a test verification in which the engagement post is engaged with the sample, and the stamp is measured by changing the air pressure in the air cavity of the upper grip and the distance between the upper and lower grips The actual bonding force between the unit and the sample is verified by comparison with the theoretical bonding force obtained by the design method. In this way, the above test method and test device can verify the bonding force obtained in the design method of the stamp unit, thereby ensuring the reliability of the design method, and the test method and test device have universal applicability.

Description

Test method and test device for bonding force between stamp unit and sample

technical field

The present application relates to the field of testing of seal units in flexible electronic technology, and more particularly to a method and a testing device for testing the bonding force between a seal unit and a sample.

Background technique

Flexible electronic technology is widely used in various fields such as biomedical monitoring due to its superior mechanical properties and material properties. These superior mechanical properties and material properties enable devices realized by flexible electronic technology to be in contact with the human body for a long time. , without affecting the normal physiological activities of the human body. Moreover, the demand for wearable medical devices made with flexible electronics technology is even more urgent today.

In order to better realize industrial production of devices realized by flexible electronic technology, those skilled in the art propose a manufacturing method for transferring circuits to flexible substrates based on traditional hard circuit processing technology. The most important process in this method is the transfer process, and the success of the transfer process directly determines whether the device can be flexible. Existing methods for transfer printing, such as using shape memory polymers, microstructures, and curvature, have certain limitations, which limit the use of these methods accordingly.

For the transfer process, the key is to adjust the strength of the interface bond between the stamp and the sample. When the sample is peeled from the donor substrate, the interfacial bonding strength between the stamp and the sample is large; when the sample is printed on the acceptor substrate, the interfacial bonding strength between the stamp and the sample needs to be kept small. This ensures that the sample can be picked up from the donor substrate during transfer and printed on the acceptor substrate. However, it is often difficult to control the parameters such as interface bonding strength. A stamp that can obtain the desired interface bonding strength with the sample is urgently needed, and the bonding force between the designed stamp and the sample needs to be tested.

SUMMARY OF THE INVENTION

The present application has been devised and completed in order to solve the above-mentioned disadvantages of the prior art. An object of the present application is to provide a method for testing the bonding force between a seal unit and a sample and a testing device, which can verify the bonding force obtained in the design method of the seal unit, thereby ensuring the reliability of the design method.

In order to achieve the above application purpose, the present application adopts the following technical solutions.

The application provides a kind of test method of the bonding force between the following seal unit and sample, it is characterized in that, described test method comprises:

Manufacture a flexible film, wherein the design parameters of the flexible film of the stamp unit are obtained by a design method of the stamp unit, and the flexible film with the bonding post is manufactured using the design parameters;

Assembling a flexible membrane and sample, where the flexible membrane is assembled to an upper clamp with an air cavity, such that the flexible membrane closes the air cavity and the engagement post faces the lower clamp, to which the sample is mounted and opposite the engagement post; and

Test verification, wherein the engagement post is engaged with the sample, and by changing the air pressure in the air cavity of the upper clamp and the distance between the upper clamp and the lower clamp, the difference between the stamp unit and the lower clamp is measured. The actual bonding force between the samples is verified by comparison with the theoretical bonding force obtained by the design method.

In an optional solution, in the step of manufacturing a flexible film, a mold is manufactured using the design parameters, a film material is cast in the mold, and the film material is taken out from the mold after curing, so as to The flexible film is obtained, and the flexible film includes a sheet-like flexible layer and a plurality of the bonding posts on one side surface of the flexible layer.

In another optional solution, 3D printing light-curable resin material is used to manufacture the mold.

In another optional solution, the membrane material is polydimethylsiloxane.

In another optional solution, in the test verification step, the types of the samples on the lower jig are changed, and the actual bonding force between the bonding posts and the samples of different types is measured.

In another optional solution, in the design method, when the stamp unit is in an initial state, the height of the joint column is set to be h, the interval between adjacent joint columns is g, and the joint column is set to be g. The diameter of the column is d, the width of the rigid base of the stamp unit in the longitudinal section is 2b, the separation length of the stamp unit and the sample in the longitudinal section is l,

为所述柔性膜的弹性模量，I_z为所述柔性膜的惯性矩，且k⁴＝d/[I_zh(d+g)]，Let p _m be the air pressure in the air cavity of the rigid substrate,

is the elastic modulus of the flexible film, I _z is the moment of inertia of the flexible film, and k ⁴ =d/[I _z h(d+g)],

Then the theoretical bonding force between the stamp unit and the sample is the following formula 1:

In another optional scheme, the critical displacement when separating between the stamp unit and the sample is the following formula 2:

Wherein γ represents the interface strength between the seal unit P and the sample S, then the maximum theoretical bonding force between the seal unit and the sample is obtained based on formula 1 and formula 2 as the following formula 3:

The present application also provides a test device using the method for testing the bonding force between a stamp unit and a sample according to any one of the above technical solutions, wherein the test device includes the upper clamp, The lower jig and the stretching machine can relatively displace the upper jig and the lower jig in directions approaching and moving away from each other.

In an optional solution, the upper clamp includes a first clamped portion and an upper clamp body, the first clamped portion is fixed to the upper clamp body, and the first clamped portion is located at the upper clamp body. Above the upper clamp body, the first clamped portion is used to be attached to the stretching machine, the upper clamp body is formed with an air cavity that opens downward, and the periphery of the opening of the upper clamp body is A glue guiding groove is formed for accommodating an adhesive, so that the flexible film can be fixed with the upper clamp.

In another optional solution, the lower clamp includes a second clamped portion and a lower clamp main body, the second clamped portion is fixed to the lower clamp main body, and the second clamped portion is located in the lower clamp body. Below the lower clamp body, the second clamped portion is used for being mounted on the stretching machine, and the lower clamp body has a slot for inserting the sample.

By adopting the above technical solutions, the present application provides a method and a device for testing the bonding force between the seal unit and the sample. The test method includes: manufacturing a flexible film, wherein the design parameters of the flexible film of the stamp unit are obtained by a design method of the stamp unit, and using the design parameters to manufacture the flexible film with bonding posts; assembling the flexible film and the sample, wherein the flexible film is assembled to have an upper clamp of the air chamber such that the flexible membrane encloses the air chamber and the engagement post faces the lower clamp, the sample is mounted to the lower clamp and opposite the engagement post; and a test verification wherein the engagement post is engaged with the sample by changing the air chamber of the upper clamp The air pressure inside and the distance between the upper clamp and the lower clamp are used to measure the actual bonding force between the stamp unit and the sample, and compare and verify the theoretical bonding force obtained by the design method. In this way, the above-described test method and test apparatus can verify the bonding force obtained in the design method of the stamp unit, thereby ensuring the reliability of the design method. Moreover, the test method and test device can be applied to the test of the bonding force between different samples and the stamp unit, and have universal applicability.

Description of drawings

Fig. 1 is a schematic structural diagram showing a seal according to an embodiment of the present application and a seal unit constituting the seal.

Fig. 2 is a schematic cross-sectional view showing the stamp unit in Fig. 1, in which a longitudinal section of the stamp unit is shown.

FIG. 3 is a schematic diagram illustrating each step of realizing the transfer process using the stamp unit in FIG. 2 .

Fig. 4 is a schematic diagram showing the step shown in (F) of Fig. 3, in which design parameters of the stamp unit are shown.

Fig. 5 is a schematic diagram showing a simplified mechanical model of the flexible membrane of the stamp unit at the step shown in Fig. 3(F).

FIG. 6 is a force analysis diagram showing the joint segment in the mechanical model in FIG. 5 .

FIG. 7 is a force analysis diagram showing the separation section in the mechanical model in FIG. 5 .

Figure 8 is a graph showing the relationship between the total energy of the system and the separation length under different displacement conditions.

Figure 9 is a graph showing the relationship between the total energy of the system and the separation length at different interface strengths.

Figure 10 is a graph showing the relationship between the total energy of the system and the separation length for a certain interface strength and displacement, but different gas pressures.

Fig. 11 is a graph showing the relationship between the displacement and the separation length under the condition of a constant gas pressure but different interface strengths.

Fig. 12 is a graph showing the relationship between displacement and separation length under conditions of a certain interface strength but different gas pressures.

Fig. 13 is a graph showing the relationship between the bonding force and the displacement under the condition of a constant air pressure but different interface strengths.

Fig. 14 is a graph showing the relationship between the maximum bonding force and the feature size under the condition of a constant gas pressure but different interface strengths.

FIG. 15 is a schematic view showing a mold for manufacturing a flexible film of a stamp unit.

FIG. 16 is a schematic view showing another mold for manufacturing the flexible film of the stamp unit.

FIG. 17 is a schematic diagram showing a measuring device for measuring the bonding force between the flexible film and the sample.

FIG. 18 is a schematic diagram showing the structure of the upper jig of the measuring device in FIG. 17 .

FIG. 19 is a schematic diagram showing the structure of a lower jig of the measuring device in FIG. 17 .

Description of reference numerals

ST Stamp P Stamp Unit 1 Rigid Substrate 11 Air Chamber 12 Air Channel 2 Flexible Membrane 21 Flexible Layer 22 Bonding Post S Sample D Donor Substrate A Acceptor Substrate

M mold 31 concave part 32 concave hole

41 The upper clamp 411 The first clamped part 412 The upper clamp body 413 The glue guide groove 42 The lower clamp 421 The second clamped part 422 The lower clamp body 43 The stretching machine.

Detailed ways

Exemplary embodiments of the present application are described below with reference to the accompanying drawings. It should be understood that these specific descriptions are only used to teach those skilled in the art how to implement the present application, and are not used to exhaust all possible ways of the present application, nor are they used to limit the scope of the present application.

Hereinafter, a seal according to an embodiment of the present application and the structure of a seal unit constituting the seal will first be described with reference to the accompanying drawings.

(Structure of a seal and a seal unit according to an embodiment of the present application)

The stamp ST according to an embodiment of the present application is used to move the sample S from the donor substrate D to the acceptor substrate A during the transfer process, and can smoothly engage with the sample S in a state where the sample S and the acceptor substrate A are engaged separation. As shown in Fig. 1, the stamp ST includes a plurality of stamp units P, and the plurality of stamp units P are arranged in a matrix array. A plurality of stamp units P are relatively independent, in particular, each stamp unit P can be independently controlled, for example, but not limited to, by designing and regulating each independent stamp unit P respectively, the stamp unit can be controlled during the transfer process. P for independent control.

As shown in Figures 1 and 2, each stamp unit P includes a rigid base 1 and a flexible membrane 2 assembled together. Specifically, the inside of the rigid base 1 is formed with an air cavity 11 and an air channel 12 that communicate with each other. The air cavity 11 has a rectangular parallelepiped shape and has a square opening that opens downward. The air channel 12 is located above the air cavity 11 and communicates with the air cavity 11 . . The flexible film 2 includes a flexible layer 21 and a plurality of bonding posts 22 . The flexible layer 21 has a sheet-like structure, and the outer edge of the flexible layer 21 is fixed to the rigid base 1 by, for example, bonding and closes the opening of the air cavity 11 . A plurality of bonding posts 22 (25 bonding posts 22 in this embodiment) are fixed to the surface of the flexible layer 21 facing away from the air cavity 11 .

It can be understood that the "rigidity" of the rigid substrate 1 here is relative to the "flexibility" of the flexible film 2 . The rigid base 1 and the flexible film 2 can be made of different materials or the same material, for example, the wall thickness of the flexible layer 21 of the flexible film 2 can be smaller than that of the rigid base 1.

In the initial state in which the stamp unit P is not in operation, a plurality of engaging posts 22 are parallel to each other, and these engaging posts 22 are arranged in a 5 x 5 matrix array with the center of the matrix array coinciding with the center of the square opening. As shown in FIG. 3, during the transfer process, the bonding post 22 is used to bond with the sample S to transfer the sample S from the donor substrate D to the acceptor substrate A, and to bond the sample S to the acceptor substrate A. In the separation step shown in FIG. 3(F), the flexible layer 21 of the flexible film 2 is deformed by changing the air pressure in the air chamber 11, so that the bonding post 22 can be separated from the sample S bonded to the acceptor substrate A. For a stamp ST including a plurality of stamp units P, the air pressures of the air chambers 11 of these stamp units P are preferably independently adjustable.

(Transfer process realized with the stamp unit according to an embodiment of the present application)

The transfer process will be described below by taking one stamp unit P as a representative. Fig. 3 shows the state of the stamp unit P in each step of the entire transfer process. In this transfer process, first, as shown in (A) and (B) of FIG. 3 , a downward displacement is applied to the whole of the stamp unit P, so that a strong bonding force is formed between the stamp unit P and the sample S; Then, as shown in FIG. 3(C), an upward displacement is applied to the stamp unit P, so that the sample S and the stamp unit P are peeled off from the donor substrate D together; further, as shown in FIG. 3(D), The stamp unit P engaged with the sample S is transferred to the acceptor substrate A, and a downward displacement is applied; then, as shown in (E) and (F) of FIG. , by applying upward displacement to the stamp unit P and adjusting the air pressure in the air cavity 11 , the bonding force between the stamp ST and the sample S is reduced, and the process of printing the sample S on the acceptor substrate A is completed.

In order to obtain the desired bonding force between the stamp unit P and the sample S in the corresponding steps in the above-mentioned transfer process, the design parameters of the stamp unit P and the control parameters of the stamp unit P can be designed as follows.

(Design method and manufacturing method of stamp unit P according to an embodiment of the present application)

In the separation step of the transfer process, in the longitudinal cross-sectional view shown in FIG. 4 , the engagement posts 22 can be in three states: the two outermost engagement posts 22 with respect to the centerline L are in a free state, and relative to the The two outermost joint columns 22 and the inner two transition joint columns 22 are in a stretched state, and the central joint column 22 is in the original length.

The main design parameters of the stamp unit P are shown through FIG. 4 . Specifically, the height of the engaging pillars 22 in the initial state is h, the adjacent engaging pillars 22 have the same interval in the initial state, and the interval between the adjacent engaging pillars 22 is g, and the engaging pillars 22 in the initial state The diameter of d is d, and the width of the rigid base 1 in the longitudinal section is 2b. The above-mentioned "longitudinal section" passes through the central axis of the plurality of joint columns 22 in a row, and the plurality of joint columns 22 are symmetrical with respect to the central line L of the longitudinal section (as shown in FIG. 4 ).

On either side of the centerline L, the transition junction columns 22 described above are present in the junction columns 22 that are not separated from the sample S. In the longitudinal section, the length between the outer edge of the transition joint post 22 and the outer edge of the rigid base 1 is set as the separation length l. Further, in the longitudinal section, the distance that the rigid base 1 moves relative to the sample S in the direction away from the sample S is the displacement v (when the stamp unit P is in the initial state of non-working, the displacement v is 0). Further, let the air pressure of the air cavity 11 in the stamp unit P be _pm . By adjusting the displacement v applied to the stamp unit P and the air pressure p _m in the stamp unit P during the transfer process, the separation length l and the bonding force F can be analyzed based on the above-mentioned main design parameters, so as to realize the interface between the stamp unit P and the sample S Intensity adjustment. The design method of the present application is realized based on this basic idea, and the design method includes the following steps: obtaining the deflection of the system, obtaining the total energy of the system, and determining the relationship between the parameters.

In the step of obtaining the deflection of the system, a mechanical model system is established according to the force of the flexible membrane 2 in the longitudinal section of the stamp unit P. Based on the separation length between the stamp unit P and the sample S in the separation step of the transfer process, the part of the flexible film 2 from the center line L to the outer edge of the transition bonding column 22 is defined as a bonding section, and the The part from the outer edge of the transition joint post 22 to the outer edge of the rigid base 1 is defined as a separation section, whereby the deformed flexible membrane 2 is equivalent to a cantilever beam structure and divided into a joint section and a separation section. Based on the deflection line differential equation of the joint section, the first deflection in the joint section is calculated, and based on the deflection line differential equation of the split section, the second deflection in the split section is calculated.

以及在AB段梁(分离段)的剪力作用F₁和弯矩M₁作用，其 中

与OA梁的变形相关；如图7所示，对于AB段梁的受力，则仅有气压p_m的作用以及OA梁和刚性基体1分别作用的剪力F₁、F₂和弯矩M₁、M₂。这样， 设

为柔性膜2的弹性模量，I_z为柔性膜2的惯性矩，

为第一挠度，x₁为以接合段的最内侧点为原点的x₁O₁y₁坐标系中的横坐标，

为第二挠度， x₂为以分离段的最内侧点为原点的x₂O₂y₂坐标系中的横坐标。Specifically, the stress state of the flexible membrane 2 is simplified to the spring cantilever beam structure shown in FIG. 5 . As shown in FIG. 6 , the corresponding OA section beam (joint section) is not only affected by the air pressure p _m , but also subjected to the tensile force of the joint column 22

and the shear force F ₁ and the bending moment M ₁ acting on the AB section beam (separated section), where

It is related to the deformation of the OA beam; as shown in Figure 7, for the force of the AB section beam, there is only the effect of the air pressure p _m and the shear forces F ₁ , F ₂ and the bending moment M acted by the OA beam and the rigid base 1 respectively. ₁ , M ₂ . Thus, let

is the elastic modulus of the flexible film 2, I _z is the moment of inertia of the flexible film 2,

is the first deflection, x ₁ is the abscissa in the x ₁ O ₁ y ₁ coordinate system with the innermost point of the joint segment as the origin,

is the second deflection, and x ₂ is the abscissa in the x ₂ O ₂ y ₂ coordinate system with the innermost point of the separation segment as the origin.

Therefore, the deflection line differential equation of the OA segment beam can be written as:

并且定义k⁴＝d/[I_zh(d+g)]。in

And define k ⁴ =d/[I _z h(d+g)].

For the analysis of OA beam, according to formula (1), it can be obtained:

The general solution corresponding to formula (2) is:

For AB segment beams, similarly, we can get:

The corresponding general solution is:

Considering the continuity conditions such as displacement, rotation angle, bending moment, shear force, etc., in the x ₁ O ₁ y ₁ and x ₂ O ₂ y ₂ coordinate systems, it can be expressed as:

Rewrite equations (3), (5) and (6) in the same coordinate system xOy with the innermost point of the OA segment as the origin, according to x ₁ =x,y ₁ =y,x ₂ =x-(bl ), and y ₂ =yv ₁ for conversion, and combined with its boundary conditions, it can be rewritten as:

The corresponding boundary conditions are:

According to equations (7) and (8), the specific expressions of coefficients C ₁ -C ₈ and w ₁ (x) and w ₂ (x) can be obtained by solving, wherein C ₁ -C ₈ are real numbers.

Further, in the step of obtaining the total energy of the system, the first bending deformation energy of the joint segment and the tensile deformation energy of the joint column 22 in the joint with the sample S in the separation step are calculated based on the first deflection obtained above, based on the Two deflections Calculate the second bending deformation energy of the separation section, calculate the interface energy between the stamp unit P and the sample S, and take the sum of the first bending deformation energy, tensile deformation energy, second bending deformation energy and interface energy as the total energy .

2)AB梁的弯曲变形能

3)接合柱22的拉 伸变形能U_pillar，4)界面能U_γ。因此系统的总能量可以表示为：Specifically, for the total energy of the above system, the total energy U _total of the system consists of four parts. 1) The bending deformation energy of the beam in the OA section

2) Bending deformation energy of AB beam

3) the tensile deformation energy U _pillar of the joint pillar 22 , and 4) the interface energy U _γ . So the total energy of the system can be expressed as:

Each part of the energy can be expressed as:

Bending deformation energy of beams in OA segment

Bending deformation energy of AB beam

The tensile deformation energy U _pillar of the joint pillar 22

The interface energy U _γ

where γ represents the interface strength between the stamp unit P and the sample S.

Further, in the step of determining the parameter relationship, the total energy calculated above is used to determine the air pressure in the cavity, the interface strength between the stamp unit P and the sample S, and the displacement of the rigid matrix 1 relative to the sample S and the separation length. The relative relationship between the seal unit P and the sample S, and the maximum bonding force between the seal unit P and the sample S, thus design the seal unit P.

是无量纲化的系统总能量，

是无量纲化的位移，

是无量纲化的 分离长度，

是无量纲化界面强度，

是无量纲化的气 压。Based on the above equations (9) to (13), the total energy of the system can be obtained. In addition, let

is the dimensionless total energy of the system,

is the dimensionless displacement,

is the dimensionless separation length,

is the dimensionless interface strength,

is the dimensionless air pressure.

的变化。当施加的位移比较小时，系统总 能量随着分离长度增加而单调递增，此时表明分离长度为0。而当系统总能 量的极小值点为系统能量的最小值时，此刻对应的分离长度为系统的实际分 离长度(图8中实心五角星点)；而当系统能量的局部最小值(图8中空心五 角星点)大于系统完全分离时

则此刻系统完全分离。如图9所 示，同样可以得到当施加位移

且界面强度

不同时无量纲化的系统总能量随着无量纲化的分离长度的变化。当系统能量单调递减(如图9中

和

)，此刻系统在无量纲化位移

印章单元P和样品S之间完全分 离。而当

和

此刻施加的位移不足以使样品S和印章单元P完 全分离，但此刻印章单元P和样品S之间存在部分分离，分离的实际长度为图 9中五角星所示。如图10所示，同样可以得到无量纲化的系统总能量在不同 气压条件下与分离长度的关系，其含义与图8、9基本相同。As shown in Fig. 8, the dimensionless total energy of the system can be obtained with the dimensionless separation length when the pressure p _m = 0 and different displacements are applied

The change. When the applied displacement is relatively small, the total energy of the system increases monotonically as the separation length increases, indicating that the separation length is zero. When the minimum point of the total energy of the system is the minimum value of the system energy, the corresponding separation length at this moment is the actual separation length of the system (the solid five-pointed star point in Figure 8); and when the local minimum value of the system energy (Figure 8) Hollow pentagram point) is greater than when the system is completely separated

The system is now completely separated. As shown in Figure 9, the same can be obtained when applying displacement

and the interface strength

The variation of the total energy of the system without simultaneous dimensionlessization with the separation length of the dimensionlessization. When the system energy decreases monotonically (as shown in Figure 9

and

), at this moment the system is in the dimensionless displacement

There is a complete separation between stamp unit P and sample S. and when

and

The displacement applied at this moment is not enough to completely separate the sample S and the stamp unit P, but there is a partial separation between the stamp unit P and the sample S at this moment, and the actual length of the separation is shown by the five-pointed star in Fig. 9 . As shown in FIG. 10 , the relationship between the total energy of the system and the separation length under different pressure conditions can also be obtained in a dimensionless manner, and its meaning is basically the same as that in FIGS. 8 and 9 .

且界面强度

不同时，随着施加位移的增加，系统的分离长 度逐渐增加，随着施加位移的增加到一定程度，系统完全分离。对应的系统 能量最小时，即为印章单元P和样品S分离长度。当界面强度为

不同 气压作用下，系统出现分离现象时，施加的位移相同，定义此刻施加的位移 为临界位移v_critical。而如图12所示，随着气压的增大，在相同的位移作用下， 系统分离长度减小。Figures 11 and 12 show the relationship between the actual separation length of the system and the applied displacement, respectively. As shown in Figure 11, when the air pressure

and the interface strength

At the same time, with the increase of the applied displacement, the separation length of the system gradually increases, and as the applied displacement increases to a certain extent, the system is completely separated. When the corresponding system energy is the smallest, it is the separation length of the stamp unit P and the sample S. When the interface strength is

Under the action of different air pressures, when the system is separated, the displacement applied is the same, and the displacement applied at this moment is defined as the critical displacement v _critical . As shown in Fig. 12, with the increase of air pressure, the separation length of the system decreases under the same displacement.

Therefore, the critical displacement required for the separation of the system can be expressed as:

The interface bonding force between the stamp unit P and the sample S can be expressed as:

Bringing in the specific expression, the specific expression of the joint force can be solved as:

The engagement force between the stamp unit P and the sample S is represented by equation (16). As shown in Fig. 13, the maximum engagement force occurs when the system and the sample S are just about to be separated. Therefore, before the separation of the system occurs, the joint force of the system increases with the increase of the applied displacement, but the maximum joint force is related to the critical displacement, so the expression of the maximum joint force can be expressed as:

其中图14示出了式(17)所表示的最大接合力和印章单元P 的特征尺寸

以及无量纲界面强度

的关系。And the specific expression of v _critical is formula (14). Defining the dimensionless maximum engagement force

Wherein Figure 14 shows the maximum bonding force expressed by the formula (17) and the characteristic size of the stamp unit P

and the dimensionless interface strength

Relationship.

之间的关系，分离长度l、施加位移v，界面强度γ和气压p_m之间的关 系已经完全可以得到。因此在实际的印章单元P设计和制造中，先通过以上 的理论计算，得到印章单元P的设计参数和使用参数，再根据得到的设计参 数和使用参数进行模具M的设计和印章单元P制造，整个制造过程如下的步 骤S1-S3所述。Based on this, the maximum bonding force _Fmax between the stamp unit P and the sample S and the characteristic size of the stamp unit P

The relationship between the separation length l, the applied displacement _v , the relationship between the interface strength γ and the air pressure pm can be completely obtained. Therefore, in the actual design and manufacture of the stamp unit P, the design parameters and use parameters of the stamp unit P are obtained through the above theoretical calculation, and then the mold M is designed and the stamp unit P is manufactured according to the obtained design parameters and use parameters. The entire manufacturing process is described in steps S1-S3 as follows.

S1: Manufacture of the flexible film 2. 15 and 16, the mold M in FIG. 15 corresponds to the flexible film 2 of a single stamp unit P of the above-mentioned embodiment, and the mold M in FIG. 16 corresponds to a plurality of stamp units P of the above-mentioned embodiments. The flexible film 2), for example, the mold M is manufactured by 3D printing or micro-nano processing, and the mold M is demolded. Then select a suitable material of the flexible film 2 for casting, and take it out from the mold M after curing. The entire flexible film 2 includes a flexible layer 21 as a base and an array of bonding pillars 22 arranged on the flexible layer 21, wherein the top of the bonding pillars 22 can increase the array of microstructures such as suction cups by changing the design structure.

S2: Rigid base body 1 is produced. By means of machining or 3D printing, the processing of the rigid substrate 1 of the stamp unit P is completed, and a cavity is formed in the stamp unit P, and the cavity includes two parts, an air cavity 11 and an air channel 12 . The air passage 12 is mainly an air passageway connected to the outside, through which the air chamber 11 is inflated and deflated from the air chamber 11 to achieve the purpose of subsequently changing the bonding force and the separation length between the flexible membrane 2 and the sample S.

S3: The manufacture of the stamp unit P and the stamp ST is completed. The rigid substrate 1 and the flexible film 2 are connected by gluing to complete the manufacture of the stamp unit P. The stamp unit P can be designed into an array shape to form a stamp ST according to the actual transfer requirements. By adjusting the air pressure of each stamp unit P in the array and the design parameters of the flexible film 2 corresponding to each unit Designed to achieve programmable transfer and interface strength adjustment.

Further, the present application also provides a method for testing the bonding force between the stamp unit P designed and manufactured by the above design method and the sample S.

(Test method for the bonding force between the stamp unit P and the sample S according to an embodiment of the present application)

After obtaining the relevant size parameters and use parameters through the above design method, the mold M as shown in FIG. 15 or FIG. 16 is manufactured by 3D printing the light-cured resin material. In the mold M, the recesses 31 are used to form the flexible layer 21 of the flexible film 2, and the recessed holes 32 are used to form the bonding posts 22 of the flexible film 2. The formed product is subjected to mold release treatment, and the flexible film 2 of the stamp unit P of the present application can be obtained.

Further, by means of 3D printing or micro-nano processing, a fixture assembly matching the stamp unit P is designed. As shown in FIGS. 17 to 19 , the clamp assembly includes an upper clamp 41 and a lower clamp 42 , the upper clamp 41 is used for mounting the flexible film 2 , and the lower clamp 42 is used for placing the sample S.

As shown in FIG. 18 , the upper clamp 41 includes a first clamped portion 411 and an upper clamp body 412 . The first clamped portion 411 is located above the upper clamp body 412 , and the first clamped portion 411 is the attachment portion of the stretching machine 43 of the upper clamp 41 . After installation, the loading of the upper clamp 41 and the stretching machine 43 is completed. The upper jig main body 412 is formed with a hollow air cavity, and has an opening that opens downward. The periphery of the opening of the upper clamp body 412 is formed as a glue guide groove 413 for accommodating glue, so that the flexible film 2 and the upper clamp 41 can be bonded and fixed. As shown in FIG. 19 , the lower clamp 42 includes a second clamped portion 421 and a lower clamp main body 422. The lower holder body 422 has a slot for inserting the sample S. The second clamped portion 421 is located below the lower clamp main body 422. By adding the second clamped portion 421 to the stretching machine 43, the loading of the lower clamp 42 and the stretching machine 43 is completed. In addition, by changing the type of the sample S inserted into the lower jig main body 422, the test of the bonding force between the different samples S and the stamp unit P can be realized.

As shown in FIG. 17 , the distance between the upper clamp 41 and the lower clamp 42 can be changed by the control unit on the right side of the clamp assembly, and the bonding force between the flexible film 2 of the stamp unit P and the sample can be measured to realize the stamp unit Bonding force test between P's flexible film 2 and sample S. The obtained results are compared with the results of the simplified model obtained in the above-mentioned design method to further verify the reliability of the design method.

The specific embodiments of the present application have been described in detail in the above content, and are also described below.

g＝d＝10^-4m，b＝10^-2m,h＝10^-3m和I_z＝10^-9m³为例进行 计算得到了这些曲线图。i. In the design method of the present application, various values of design parameters and use parameters can be used for calculation, so as to obtain an optimized design scheme through the design method of the present application. As shown in Figure 8 to Figure 14, to

These graphs are obtained by calculating g=d= ^10-4m , b ^{= 10-2m} , h= ^10-3m and _Iz = ^10-9m3 as examples.

ii. The mold M and the clamps 41 and 42 involved in this application are all processed with 3D printing photocurable resin materials, and the material used for the flexible film 2 to be manufactured is polydimethylsiloxane (PDMS). In addition, in the testing process, the real stamp ST or the stamp unit P is not used for testing, but the upper jig 41 is used instead of the specific stamp ST, so that the test method has universal applicability.

iii. This application proposes a design method for the stamp unit P used for transfer printing. Through specific mechanical analysis, the use parameters of the design parameters of the stamp unit P are obtained, and the quantitative design of the stamp ST can be given. Controllable adjustment is more precise. The present application also proposes a method for manufacturing the above-mentioned stamp unit P, the stamp unit P manufactured by this method can realize independent adjustment of the interface bonding strength, and at the same time, the stamp ST composed of a plurality of such stamp units P can realize a systematic Controllable operation, enabling large-scale programmable transfer, which can achieve complex transfer patterns. The present application, through theoretical design, optimizes the design of the seal ST from the structural level, which can greatly reduce the technical requirements of the transfer to the operator, greatly reduce the technical difficulty of the operation, and make the transfer step more convenient and easy to operate. The present application also proposes a method for testing the bonding force between the stamp unit P and the sample S, which has universal applicability. By replacing the samples S in the lower jig 42, the interface bonding strength test between the stamp ST and various samples S can be realized.

Claims (5)

1. A method of testing a bonding force between a stamp unit and a sample, the method comprising:

manufacturing a flexible film (2), wherein design parameters of the flexible film (2) of the stamp unit (P) are obtained through a design method of the stamp unit (P), and the flexible film (2) with the joint columns (22) is manufactured by utilizing the design parameters;

assembling a flexible membrane (2) and a sample (S), wherein the flexible membrane (2) is assembled to an upper fixture (41) having an air cavity such that the flexible membrane (2) encloses the air cavity and the binding posts (22) face a lower fixture (42), the sample (S) is mounted to the lower fixture (42) and opposite the binding posts (22); and

a test verification in which the engagement post (22) is engaged with the sample (S), an actual engagement force between the stamp unit (P) and the sample (S) is measured by changing the air pressure in the air chamber of the upper jig (41) and the distance between the upper jig (41) and the lower jig (42), and a verification is compared with a theoretical engagement force obtained by the design method,

in the design method, the height of the joint columns (22) is h, the interval between the adjacent joint columns (22) is g, the diameter of the joint columns (22) is d, the width of a rigid base body of the stamp unit (P) in a longitudinal section is 2b, the separation length of the stamp unit (P) and the sample (S) in the longitudinal section is l, and the distance of the rigid base body moving relative to the sample (S) in the longitudinal section towards the direction far away from the sample (S) is displacement v,

let p_mIs the air pressure in the air cavity of the rigid substrate,

is the elastic modulus, I, of the flexible film (2)_zIs the moment of inertia of the flexible membrane (2), and k⁴＝d/[I_zh(d+g)]，

The theoretical bonding force between the stamp unit (P) and the sample (S) is the following formula 1:

setting a critical displacement of the rigid matrix in the longitudinal section relative to the sample (S) moving in a direction away from the sample (S) as v_criticalWhich is represented by formula 2 below:

wherein γ represents the interface strength between the stamp unit P and the sample S, the maximum theoretical bonding force between the stamp unit P and the sample S is obtained based on the following formula 1 and formula 2, and is represented by formula 3:

2. the method for testing the coupling force between a stamp unit and a sample according to claim 1, wherein in the step of manufacturing the flexible film (2), a mold (M) is manufactured using the design parameters, a film material is cast in the mold (M), and the film material is taken out of the mold (M) after being cured, thereby obtaining the flexible film (2), and the flexible film (2) includes a sheet-shaped flexible layer (21) and a plurality of the coupling posts (22) on one side surface of the flexible layer (21).

3. Method for testing the coupling force between a stamp unit and a sample according to claim 2, characterized in that said mould (M) is made of 3D printed light-curable resin material.

4. The method for testing the coupling force between a stamp unit and a sample according to claim 2 or 3, wherein the film material is polydimethylsiloxane.

5. The method for testing the coupling force between a stamp unit and a sample according to any one of claims 1 to 3, wherein in the step of test verification, the kind of sample (S) on the lower jig (42) is changed, and the actual coupling force between the coupling post (22) and the different kind of sample (S) is measured.

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