WO2016076671A1

WO2016076671A1 - Method and apparatus for testing flexible element

Info

Publication number: WO2016076671A1
Application number: PCT/KR2015/012248
Authority: WO
Inventors: 김덕기; 류호준; 현승민; 장봉균
Original assignee: 세종대학교산학협력단; 한국기계연구원; 한국전자통신연구원
Priority date: 2014-11-13
Filing date: 2015-11-13
Publication date: 2016-05-19

Abstract

According to the present invention, provided are a method and an apparatus for testing a flexible element, the method comprising: a step for fixing, to a main body unit, a flexible element to be measured; a step for making an electrical connection unit, which includes one or more electrode pads arranged along the circumference of a support surface included in the main body unit, and the flexible element to electrically come into contact with each other; a step for adjusting the pressure of a chamber by putting/withdrawing a medium into/from the chamber included in the main body unit; and a step for testing the flexible element deformed by the stress induced from the pressure of the chamber.

Description

Test method and device of flexible device

The present invention relates to a test method and apparatus for evaluating the electrical and mechanical properties of a flexible device in a bulge, bulge or shrinkage state.

Unlike the device formed on the rigid substrate, the flexible device maintains the characteristics of the device even when repeated stress is applied and has the property of easily bending. Therefore, the flexible element may be used in a flexible electronic component such as a flexible display, a touch screen, or a sensor attachable on a free curved surface.

In the prior art, the flexible device is generally manufactured in a film form by mixing a ceramic / metal material with a flexible polymer material, and then made through a subsequent process such as electrode deposition. Alternatively, a device may be implemented using a semiconductor process on a substrate or a wafer for a semiconductor, and the device may be implemented through an etching process and a transfer process.

Recently, a technology using a plastic substrate that is light, impact resistant and bendable has been developed. In this regard, Korean Patent Laid-Open No. 10-2009-0083087 (name of the invention: a thin film transistor, a method for manufacturing the same, and a flexible display device including the thin film transistor) includes a thin film transistor including a flexible substrate, which simplifies the manufacturing process. It is starting.

In general, a thin film transistor includes a gate electrode formed on a substrate, a semiconductor layer insulated from the gate electrode by a gate insulating layer, and including a channel region, a source region and a drain region, and a source electrode and a drain electrode in contact with the source region and the drain region. Include.

1 is a result of measuring the mechanical and electrical properties of a thin film transistor including a conventional flexible substrate. Specifically, the mechanical and electrical properties of the permanently deformed substrate are induced by inducing deformation on the flexible substrate.

In detail, (a) of FIG. 1 shows a thin film transistor formed of carbon nanotubes on a flexible substrate, and (d) shows an optical transmission of the flexible substrate and an optical state of a carbon nanotube thin film transistor formed on a flexible substrate. The transmittance is shown. Also, (b) shows I _D -V _GS transfer characteristics of the top-gate of the thin film transistor. In this case, the I _D -V _GS transfer characteristic means a relationship between the drain current I _D and the voltage V _GS between the gate and the source.

Further, (e) denotes an I _D -V _DS output characteristics on the thin film transistor, wherein the I _D -V _DS is a drain current (I _D) and the drain-refers to the relationship between the source voltage (V _DS). (c) shows the strain according to the degree of bending of the substrate, (f) shows the on / off current according to the strain of the substrate. In particular, referring to FIG. 1C, the strain of the substrate may be derived through the bent angle dθ of the substrate, the radius of curvature D, and the thickness d of the substrate.

As such, the prior art induced deformation on the flexible substrate, thereby measuring the mechanical and electrical properties of the permanently deformed substrate. In other words, in order to produce a flexible device having mechanical and electrical characteristics desired by the user, various kinds of plastic deformation substrates have to be manufactured, and in the case of elastic deformation substrates, measurement is impossible. There was a problem.

Some embodiments of the present invention aim to propose a test method and apparatus for deforming a flexible device stepwise in an expanded, expanded or contracted state, thereby evaluating the electrical and mechanical properties of the flexible device.

As a technical means for achieving the above-described technical problem, the test method of the flexible device according to the first aspect of the present invention is a step of fixing the flexible device to be measured to the main body, along the circumference of the support surface included in the main body Electrically contacting a flexible device with an electrical connection including at least one electrode pad disposed thereon, adjusting a pressure of the chamber by inputting or outputting a medium into the chamber included in the body part, and induced by the pressure of the chamber. Testing the flexible element deformed by stress.

The flexible device test apparatus according to the second aspect of the present invention includes a main body portion including a chamber and a support surface on which the flexible element is to be mounted, a main body portion, and an input unit through which a medium for adjusting pressure of the chamber is input, and formed in the main body portion. And an output part for outputting the medium, a clamping part for fixing the flexible element to the support surface, and a clamping part, which is formed along a circumference of the support surface and a window part for exposing a portion of the flexible element. An electrical connection including at least one electrode pad for electrical contact, and a control unit for adjusting the pressure of the chamber through the control of the input and output. At this time, the stress is provided to the flexible device according to the pressure of the chamber.

According to any one of the problem solving means of the present invention described above, in the expanded, expanded or contracted state of the flexible device, the mechanical and electrical characteristics of the flexible device can be grasped. In addition, the deformation of the flexible element due to expansion, expansion or contraction can be measured step by step.

1 is a result of measuring the mechanical and electrical properties of a thin film transistor including a conventional flexible substrate.

2 is a view showing a test apparatus of a flexible device according to an embodiment of the present invention.

3 is a view showing a test apparatus of a flexible device according to another embodiment of the present invention.

4 is a flowchart illustrating a test method of a flexible device according to an exemplary embodiment of the present invention.

5 is an expected result of the electrical characteristics of the device using the flexible device test apparatus according to an embodiment of the present invention.

6 is an expected result of the mechanical properties of the device using the flexible device test apparatus according to an embodiment of the present invention.

DETAILED DESCRIPTION Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily implement the present invention. As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present invention. In the drawings, parts irrelevant to the description are omitted in order to clearly describe the present invention, and like reference numerals designate like parts throughout the specification.

Throughout the specification, when a part is "connected" to another part, this includes not only "directly connected" but also "electrically connected" with another element in between. . In addition, when a part is said to "include" a certain component, which means that it may further include other components, except to exclude other components unless otherwise stated.

For reference, the flexible device described throughout the present specification may include an active device that may be used in a passive device and a thin film transistor formed by forming a thin film by a method such as deposition or sputtering on a substrate having good insulation.

For example, when a flexible device is used in a thin film transistor, the thin film transistor is insulated from the gate electrode by a gate electrode and a gate insulating film formed on the flexible device serving as a substrate and includes a channel region, a source region and a drain region. And a source electrode and a drain electrode in contact with the semiconductor layer and the source region and the drain region.

In addition, the flexible device used at this time is a polymer film, polyester (polyester), polyvinyl (polyvinyl), polycarbonate (polycarbonate), polyethylene (polyethylene), polyacetate (polyacetate), polyimide, polyether sulfone (polyethersulphone; PES), polyacrylate (polyacrylate; PAR), polyethylene naphthelate (PEN), polyethyleneterephehalate (PET), elastomer (elastomer), PDMS (polydimethylsiloxane), etc. It may be made of.

In general, in the thin film transistor, the gate electrode may be formed of a conductive metal, carbon nanotube (CNT), graphene, and the like, and the semiconductor layer may be formed of an inorganic semiconductor, an organic semiconductor, or an oxide semiconductor. have. The source electrode and the drain electrode may be formed of a metal, a carbon nano tube (CNT), graphene, or the like.

In addition, the gate insulating film is formed by applying an inorganic material such as HfOx, TiOx, SiOx, SiNx, AlOx, or other organic materials such as PVA, PVP, PMMA, which can be processed at low temperature (for example, 200 ° C. or lower) by a conventional coating method can do.

The semiconductor layer should be formed at a temperature lower than the melting temperature of the flexible element. Therefore, chemical vapor deposition (CVD) or physical vapor deposition (PVD) methods which can be processed at a temperature of 200 ° C. or less can be used. The semiconductor layer may be formed of an inorganic semiconductor such as silicon (Si), an organic semiconductor such as polyacetylene, polythiophene, polypyrrole, polyaniline, or zinc oxide (ZnO) or copper oxide. It can be formed from an oxide semiconductor containing (CuOx) or the like as a main component.

In addition, the source electrode and the drain electrode may be formed of a metal. For example, the source electrode and the drain electrode may be formed by mixing metals such as gold (Au), silver (Ag), platinum (Pt), and the like in an organic solvent, and then printing and curing the ink. In the case of a thin film transistor using a flexible device, since the flexible device bends well, the source electrode and the drain electrode may be manufactured by printing a metal by an inkjet method. Since the inkjet method does not need to use a mask, a mask saving effect can be obtained.

As described above, the flexible element can be used in the thin film transistor, and can flexibly cope when the substrate is to be moved or the substrate is bent to insert the component element.

In addition, a thin film for various functions may be formed on one surface of the substrate formed of the flexible element. Furthermore, not only a semiconductor chip but also a plurality of devices such as a capacitor, a solar cell, a thermoelectric element, and a battery may be mounted as the electronic element. Therefore, in order to develop and apply a flexible device, an apparatus and method for evaluating the characteristics of the flexible device are needed.

For reference, throughout the specification, the term “deformation” refers to a state in which the swelling is bulky due to swelling, and “expansion” refers to a state of bulging and protrudes, and “shrinkage” refers to expansion and It refers to a state of returning to the original state from the expanded state, or the state of shrinking in volume or scale within the elastic limit of the flexible element.

Hereinafter, a test apparatus and a method of a flexible device according to an embodiment of the present invention will be described with reference to the drawings.

Referring to FIG. 2A, the test apparatus 10 of the flexible device may include a main body 100, an input unit 200, an output unit 300, a clamping unit 400, a window unit 500, and an electrical connection unit. 600, the control unit 700, and the O-ring member 800.

In some cases, the test device 10 of the flexible device may include an electrical property measuring device 900 for measuring electrical properties of the flexible device, a mechanical property measuring device (not shown) for measuring mechanical properties, and a heating device ( 1000) may be further included. Herein, the mechanical property measuring device may be any device that can measure the height of the flexible device when it is expanded, expanded or contracted to rise or contract.

Referring to the test device 10 of the flexible device in more detail, first, the main body 100 may include a chamber 110 and a support surface 120 on which the flexible device is mounted. The chamber 110 may be located on the lower surface of the main body 100, and the support surface 120 may be located along the circumference of the upper end surface of the chamber 110.

At this time, the chamber 110 may accommodate the medium, and may receive the pressure in the chamber 110. Herein, the medium may include oil, gas, distilled water, and the like, but is not limited thereto.

In particular, the input unit 200 and the output unit 300 formed in the main body unit 100 may input or output a medium. The input unit 200 and the output unit 300 may be located anywhere in the main body unit 100, but an easy place for inputting and outputting a medium is preferable.

The support surface 120 of the body portion 100 may mount the flexible element. In this case, a clamping part 400 may be formed to fix the flexible element to the support surface 120. In addition, the clamping part 400 may be provided with a window part 500 to expose a portion of the flexible element.

Referring to FIG. 2C, an area of a hole drilled in the clamping part 400 is the window part 500. Therefore, when the flexible element is fixed on the support surface 120 by the clamping part 400, one side of the flexible element is exposed toward the chamber 110 through the window portion 500, thereby to the chamber 110. Can be in contact with the stored media.

Thereafter, the pressure in the chamber 110 may be adjusted by the input or output of the medium, and thus, the flexible element may be inflated, expanded or contracted and bent toward the inside or outside of the chamber 110. For reference, the window 500 may be in the form of any one of a circle, a rectangle, a square, and an oval.

FIG. 2 (d) shows a circular window portion 500. Depending on the shape of the window 500, the stress state applied to the area of the flexible element may vary. When the window portion 500 is square or circular, the stress state applied to the flexible element is a biaxial stress state. In addition, when the window 500 is rectangular or elliptical, the stress state applied to the flexible element may be a uniaxial stress state.

When the window portion 500 is circular, biaxial stress is applied to the entire area of the flexible element, and stresses such as square or rectangle are concentrated to minimize the case where pressure is applied to a portion that is not desired by the user. have.

Next, the O-ring member 800 is disposed along the circumference of the upper end surface of the chamber 110. The O-ring member 800 when the flexible element is mounted on the support surface 120 located on the upper end surface of the chamber 110 (FIG. 2C), the flexible element, the clamping part 400, and the chamber 110. It is possible to strengthen the contact between the upper end of the). Therefore, the O-ring member 800 is preferably located between the upper end surface of the chamber 110 and the flexible element.

In addition, according to an embodiment of the present invention, after mounting the flexible element on the support surface 120, the electrical connection 600 including one or more electrode pads 610 disposed along the circumference of the support surface 120 And (e) of FIG. 2. In this case, the electrical connection unit 600 may measure an electrical signal that changes as the flexible device gradually changes due to expansion, expansion, or contraction in real time.

The electrical connection unit 600 is connected to the electrical characteristic measuring device 900 and may be connected to the flexible device through wire bonding. The electrical characteristic measuring apparatus 900 may output a voltage or current signal for detecting electrical characteristics with respect to the connected flexible element, and calculate an electrical characteristic based on the voltage or current signal detected from the electrode of the flexible element.

In more detail, the electrical characteristic measuring apparatus 900 may measure I _D -V _GS transfer characteristics representing a relationship between the drain current I _D of the top-gate and the voltage V _GS between the gate and the source of the flexible device. And I _D -V _DS output characteristics indicating the relationship between the drain current I _D and the voltage V _DS between the drain and the source can be measured. In addition, the on / off current of the thin film transistor can be measured. Mobility, threshold voltage, slope of sub-threshold voltage, etc. can be calculated based on the measured electrical characteristics.

Next, the controller 700 may control the entry and exit of the input unit 200 and the output unit 300. For this reason, the pressure in the chamber 110 can be adjusted. In addition, the controller 700 may include a pressure sensor and a pressure controller, the accuracy of which is preferably within the error range of 1%.

For example, when the controller 700 closes the output unit 300 and controls the input unit 200 to input the medium, the pressure in the chamber 110 is higher than the pressure of the external environment, thereby causing the chamber 110 and The connected flexible element is pressured in a direction outside the chamber 110 inside the chamber 110.

On the contrary, Figure 3 is a view showing a test device of the flexible device according to another embodiment of the present invention. Referring to FIG. 3, it can be seen that the flexible element is bent in the direction of the interior of the chamber 110. This is a case where the control unit 700 adjusts the output unit 300 to close the input unit 200 and output the medium. That is, the pressure in the chamber 110 is lower than the pressure of the external environment, so that the flexible element connected to the chamber 110 may be bent in the direction of the inside of the chamber 110 from the outside of the chamber 110.

As such, when the controller 700 controls the pressure in the chamber 110, the flexible element fixed to the support surface 120 of the chamber 110 may be deformed. In this case, the degree of deformation may be measured through a mechanical characteristic measuring instrument, and the change in electrical characteristics due to deformation may be measured by the electrical characteristic measuring apparatus 900.

In this case, deformation may be induced in a state in which heat is applied using a heating device 1000 such as a halogen lamp or a heater from the outside.

Mechanical properties of flexible devices that can be measured by measuring instruments include height and displacement due to expansion, expansion or contraction, residual stress, Young's modulus, yield strength and tensile strength. (tensile strength), the ratio of transverse and longitudinal strain (poisson ratio), the coefficient of thermal expansion (CTE), the creep properties, and the stress-life curves.

In general, the mechanical properties are measured by the nano-indentation test, the expansion or bulge test (bulge test), the bending test (bending test), the micro-tension test method.

The nano indentation test is a method of performing the indentation test with a tester at a constant frequency and amplitude and evaluating the mechanical properties of the thin film using the dynamic response characteristics of the test piece. That is, the load and displacement generated while indenting the indenter into the material can be continuously measured, and the area of the indentation can be inferred from the measured displacement and load, thereby measuring residual stress, viscoelastic properties, and flow curves. have.

On the other hand, in the expansion or expansion test method, the flexible element is deformed by a gas or a liquid, and by measuring the deformation, the relationship between the stress and the deformation of the thin film can be calculated. Normally, the strain is measured by an interferometry or capacitive gauge. The elasticity and plastic behavior of the material can be determined by measuring the height of the thin film of the flexible element deformed by the expansion or expansion test method. In particular, by measuring the difference in the refractive index of the comparison group and the control group by using an interferometer method using a laser can determine the degree of deformation of the comparison group.

The bending test method measures the mechanical properties of a flexible device by applying a bending state by moving a movable jig relative to a fixed jig using a motor or the like.

Next, the tensile test method can measure the degree of extension of the flexible element by applying a load after fixing the flexible element. For example, both ends of the test piece are fixed to the tester, and a tensile force (pulling force) is applied in both directions of the test piece axis, and then the difference between the refractive indexes of the comparison group and the control group is measured by an interferometer method. The degree of deformation can be known.

On the other hand, the electrical characteristic measuring device 900 outputs a voltage or current signal for detecting electrical characteristics to the flexible element connected through wire bonding, and based on the voltage or current signal detected from the electrode of the flexible element Can be calculated.

In particular, in order to measure the DC characteristics of the flexible element, it is preferable to use an electronic test system together, and the accuracy is at least within an error range of ± 0.1%. For example, since the small current passed can often be the gate leakage current, when the gate leakage current is 1 pA, the resolution of the equipment should be 1 fA or smaller.

In addition, it is important to maintain the environment under the same conditions because the flexible element is affected by the ambient humidity and temperature. At this time, the change in temperature is preferably less than 2 degrees.

The heating device 1000 used to maintain the temperature condition or used to heat the flexible element itself may be implemented as a heater or a halogen lamp. For example, the heating device 1000 is in the form of a heater. When implemented, as shown in (a) of FIG. 2, it may be located at the bottom of the chamber 110 to transfer heat energy to the chamber 110. Accordingly, the medium in the chamber 110 is actively moved, it is possible to transfer the heat energy to the flexible element. On the other hand, when the heating device 1000 is implemented in the form of a halogen lamp, as shown in Figure 2 (b), it may be positioned at a predetermined interval on the upper end of the flexible element. In this manner, the heating device 1000 may be any device that can apply thermal energy to a flexible element such as a heater or a halogen lamp.

For reference, before the test of the flexible device, it is necessary to secure the mechanical and electrical property values of the unmodified flexible device that can be compared with the mechanical and electrical property values of the flexible device deformed due to expansion, expansion or contraction.

In addition, several conditions must be maintained. First, the process of a transistor made of a flexible device must be kept the same. In particular, it is desirable to keep the flexible device from being peeled into a thin layer or forming defects during the process.

Next, the size of the flexible device to be tested is preferably larger than the window 500. For example, when the size of the flexible element is smaller than the window portion 500, it is difficult to support the clapping portion 400, and when the size of the window portion 500 and the flexible element are similar, the expansion, expansion or contraction may be applied. When the flexible element is deformed, the flexible element may be bent and smaller than the window part 500. In this case, since the window part 500 is not sealed with the flexible element, the inside of the chamber 110 may be exposed to air, and thus it may be difficult to maintain the pressure of the chamber 110.

Next, in order to obtain accurate elasticity and plastic behavior, it is preferable to accurately measure the thickness and dimension of the flexible element and the flexible substrate.

In addition, the manufactured flexible device should be stored well to prevent oxidation. When the transistor is manufactured using the flexible device, the measurement may not be performed properly due to the change of electrochemical properties due to the storage environment.

In addition, when the liquid medium is filled in the chamber 110, it is preferable that air bubbles are not generated so as not to cause a change in physical properties due to air bubbles.

Referring back to FIG. 4, in the method of testing a flexible device according to an embodiment of the present invention, the fixing of the flexible device to be measured to the main body unit 100 (S410) and the support included in the main body unit 100 is performed. Electrically contacting the flexible device and the electrical connection part 600 including one or more electrode pads 610 disposed along the circumference of the surface 120 (S420), and the chamber 110 included in the main body part 100. Controlling the pressure of the chamber 110 by inputting or outputting the medium to the medium (S430), and testing the flexible element deformed by the biaxial stress induced by the pressure of the chamber 110 (S440). .

In particular, the testing of the flexible device at this time (S440) can measure the mechanical and electrical properties.

In the test method of the flexible device, first, the flexible device to be measured is fixed to the main body unit 100 (S410).

In this case, the flexible element may be fixed along the circumference of the support surface 120 while covering the window portion 500. At this time, it can be mechanically fixed using the clamping unit (400). In addition, it can be completely sealed through epoxy gluing. At this time, it is desirable to prevent unwanted wrinkles, bends, sheer stress and the like.

In addition, in order to prevent unwanted leakage of the user, the O-ring member 800 may be disposed between the flexible element, the clamping part 400, and the upper end surface of the chamber 110 to strengthen the contact state.

Next, when the flexible device is fixed to the main body unit 100 in the previous step (S410), including one or more electrode pads 610 disposed along the circumference of the included support surface 120 of the main body unit 100 The electrical contact portion 600 and the flexible element is in electrical contact (S420).

At this time, the flexible element and the electrical connection 600 may be wire-bonded to make electrical contact.

Next, when the preparation for measuring the flexible device in the previous step (S420) is finished, the medium is input or output to the chamber 110 included in the body portion 100 to adjust the pressure of the chamber 110 (S430). .

In order to obtain quasi-static deformation from the flexible element, the pressure is preferably increased or decreased sequentially. The pressure range is preferably 10 ⁻⁹ / s to 10 ⁻⁴ / s.

Next, the flexible device deformed by the expansion, expansion or contraction induced by the pressure of the chamber 110 adjusted in the previous step (S430) is tested (S440).

At this time, the mechanical and electrical characteristics of the flexible device can be tested. Here, I _D -V _GS transfer characteristics representing the relationship between the drain current I _D of the top-gate and the voltage V _GS between the gate and the source can be measured, and the drain current I _D and the drain-source can be measured. I _D -V _DS output characteristics indicating the relationship between the voltage (V _DS ) can be measured. In addition, from the measured transfer curve, V _th (ci), V _th (ext), I _d (sat), I _d (lin), I _d (leak), G _m (max), μ ( parameters such as lin), μ (sat), and SS can be extracted. Next, each parameter will be described in more detail.

First, V _th (ci) means a constant current threshold voltage, and can be defined by the following equation.

[Equation 1]

The above equation is for the linear range (V _ds = 0.05 ~ 0.1V), and V _th (ci) is the gate voltage when I _d has a value of 0.1 μA X gate width.

Next, V _th (ext) means extrapolated threshold voltage, and can be defined by the following equation.

[Equation 2]

The above equation is for the linear range (V _ds = 0.05 ~ 0.1V). V _th (ext) is a gate voltage when the slope of I _d -V _gs becomes maximum. V _gs _{(gm (max))} is a gate voltage when gm This is the _{_{maximum, I d (gm (max)}} ) refers to a drain current when the V _gs value is the V _gs _{(gm (max))} . gm _(max) is a value when DC conductivity is maximum.

Next, I _d (sat) means saturated drain current and is the drain current when the values of V _ds and V _gs are typical supply voltage values under driving conditions.

Next, I _d (lin) stands for linear drain current, where V _ds is a value between 0.05V and 0.1V and V _gs is the drain current when it has a typical supply voltage under operating conditions. it means.

Next, I _d (leak) means drain leakage current, V _ds is a typical supply voltage under driving conditions, and a drain current when V _gs is zero.

Next, Gm (max) means maximum trans-conductance. Gm is the slope of I _d -V _gs , and Gm (max) is the interconductance value measured when V _gs is equal to V _th (ext). Here, it is preferable to keep the V _ds value in the linear region.

Next, μ (lin) means linear mobility, which can be calculated from the slope of I _d -V _gs , and follows the following equation.

[Equation 3]

The above equation corresponds to a linear range (V _ds = 0.05 to 0.1V), where C _g is the capacitance of a given gate oxide, W is the gate width, and L is the gate length.

Next, μ (sat) means saturated mobility, and can be calculated using the following equation in I _d -V _gs .

[Equation 4]

The saturation range is (V _ds ≥ V _gs -V _th ), C _g means capacitance of a given gate oxide film, W means gate width, and L means gate length.

Next, SS denotes a sub-threshold slope, and thus, it is possible to measure how efficiently the conductive channel is formed in the device and calculate it by using the following equation.

[Equation 5]

SS is the slope of the V _gs -log10 (I _d ) curve, and Log10 (I _d ) and V _gs graphs show the approximate log linear behavior in the driving region of the thin film transistor with V _ds fixed.

Next, mechanical properties such as expansion, expansion or contraction degree, displacement, etc. of the flexible element can be obtained from the mechanical property measuring device. Here, mainly the expansion, expansion or shrinkage test was used. By measuring the deformed height from the mechanical property measuring instrument, mechanical properties such as stress-strain (strain) of the flexible device can be extracted.

On the other hand, as a representative device of the mechanical characteristic measuring device, measuring equipment using a laser interferometry such as Michelson interferometry can measure the height of the expanded or expanded state. Looking at the principle of measurement, first, the source beam can be separated into two separate beams through an optical arrangement. One beam is reflected from the expanded surface and returned to the measuring device. This can be recombined with the other beam reflected from the reference mirror. The difference in path lengths of the two beams may generate a band-shaped pattern, and the band-shaped pattern may be composed of a black band and a light band. Therefore, the expansion, or the degree of expansion of the flexible element can be confirmed by measuring the number of bands formed by the beam that is refracted.

Photo detectors and spot infrared laser light sources can measure the maximum refraction of an expanded or expanded flexible device. In general, the degree of inflation to the maximum height or the maximum degree of refraction can be measured at the center of the flexible element. In this case, the laser would have to be positioned so that the center of the flexible element is illuminated vertically.

In addition, by measuring the mechanical characteristics according to the deformation of the flexible element by the above-described method, the change in capacitance can also be measured, it is possible to measure the stress applied to the flexible element by the thickness of the flexible element, the change in capacitance, the pressure. At this time, the change in height and capacitance can be obtained from conventional mathematical calculations.

On the other hand, Figure 5 is an expected result of the electrical characteristics of the device using the flexible device test apparatus according to an embodiment of the present invention.

Referring to FIG. 5, electrical characteristics such as V _th , SS, and mobility may be extracted from I _D and V _GS curves of a thin film transistor using a flexible device through an embodiment of the present disclosure.

The fluidity in the linear domain can be extracted from the slope of the linear domain of the I _D and V _GS (= V _G ) graphs, and the point where the extrapolated straight line of the linear domain meets the X-axis is V _th (= V _T) Voltage) value (Fig. 5 (a)). Where V _D is equal to V _ds . Μn is also the same as μ and μ_bar.

The fluidity (I _D (sat)) ^1/2 and V _GS of the possible extraction from the slope of the graph and points the extrapolated straight line of intersection with the X axis the saturation region V _th (= V _T, the threshold voltage) value at the saturation region (B) of FIG. 5).

SS (= S) can be extracted from a graph of I _D (log scale) and V _GS (linear scale) (Fig. 5 (c)). The SS value of a single crystal Si transistor is usually 70 mV / decade, and a small SS value means that the transistor turns on quickly from off to on.

In addition, an example of mechanical property evaluation results can be seen through FIG. 6. 6 is an expected result of the mechanical properties of the device using the flexible device test apparatus according to an embodiment of the present invention.

In particular, Figure 6 is a result showing the relationship between the pressure for the Ag-Pd / SiNx and the height of expansion or expansion. Mechanical properties such as residual stress and modulus can be extracted from the slopes and intercepts of the p / h and h2 graphs.

As described above, the test method and apparatus of the flexible device according to an embodiment of the present invention can measure the electrical and mechanical properties of the device manufactured on the flexible substrate. In addition, the deformation of the flexible element due to expansion, expansion or contraction can be measured step by step. In addition, it is also possible to measure the reliability characteristics by conducting the characteristic evaluation through a repeated test or the like while applying heat using a heat applying mechanism.

The foregoing description of the present invention is intended for illustration, and it will be understood by those skilled in the art that the present invention may be easily modified in other specific forms without changing the technical spirit or essential features of the present invention. will be. Therefore, it should be understood that the embodiments described above are exemplary in all respects and not restrictive. For example, each component described as a single type may be implemented in a distributed manner, and similarly, components described as distributed may be implemented in a combined form.

The scope of the present invention is shown by the following claims rather than the above description, and all changes or modifications derived from the meaning and scope of the claims and their equivalents should be construed as being included in the scope of the present invention. do.

Claims

In the test method of the flexible element,

Fixing the flexible element to be measured to the main body;

Electrically contacting the flexible device with the electrical connection part including at least one electrode pad disposed along a circumference of the support surface included in the main body;

Adjusting the pressure of the chamber by inputting or outputting a medium into the chamber included in the main body; And

Testing the flexible element deformed by the stress induced by the pressure of the chamber.
The method of claim 1,

Testing the flexible device is

Test method of a flexible device comprising measuring the electrical properties of the flexible device.
The method of claim 1,

Testing the flexible device is

Test method for a flexible device comprising measuring the mechanical properties of the flexible device.
The method of claim 1,

Electrically contacting the flexible device is

And a wire bonding contact with the electrical connection portion to output a voltage or current signal to detect an electrical characteristic with respect to the flexible element.
In the test apparatus of the flexible element,

A main body including a chamber and a support surface on which the flexible element is mounted;

An input unit formed in the main body unit and receiving a medium for adjusting the pressure of the chamber;

An output part formed in the main body part and outputting the medium;

A clamping part for fixing the flexible element to the support surface;

A window portion formed in the clamping portion and exposing a portion of the flexible element;

An electrical connection portion disposed along a circumference of the support surface and including one or more electrode pads for electrical contact with the flexible element; And

It includes a control unit for adjusting the pressure of the chamber through the control of the input unit and the output unit,

The control unit is a flexible device test device for providing a stress to the flexible device in accordance with the pressure of the chamber.
The method of claim 5, wherein

Further comprising an electrical characteristic measuring device for measuring the electrical characteristics of the flexible device,

The electrical characteristic measuring device outputs a voltage or current signal for detecting electrical characteristics with respect to the flexible element connected to the electrical connection through the wire bonding,

And a device for calculating electrical characteristics based on a voltage or current signal detected from an electrode of the flexible device.
The method of claim 5, wherein

The chamber is located on the lower surface of the body portion, the support surface is a test device of the flexible device is located along the circumference of the upper end surface of the chamber.
The method of claim 5, wherein

The window portion

Test device for a flexible device of any one of circular, rectangular, square, and oval.
The method of claim 5, wherein

Arranged along the periphery of the upper end surface of the chamber, further comprising an O-ring member for strengthening the contact between the flexible element, the clamping portion and the upper end surface of the chamber.
The method of claim 5, wherein

The apparatus for testing a flexible device further comprises a mechanical property measuring device for measuring the mechanical properties of the expansion, expansion or contraction of the device.
The method of claim 5, wherein

And a heating device capable of adjusting the temperature in the chamber.
The method of claim 11,

The control unit

Test device for a flexible device that evaluates the reliability through a repeated test in the state of applying heat using the heating device.