阅读说明：本技术 薄膜材料热膨胀系数的测试装置 (Testing device for thermal expansion coefficient of thin film material ) 是由 刘泽文 张玉龙 于 2021-01-12 设计创作，主要内容包括：本发明公开了一种薄膜材料热膨胀系数的测试装置,包括热膨胀系数测试结构、加热结构和射频测试仪器。其中,热膨胀系数测试结构包括衬底、射频传输线和热膨胀系数测试MEMS结构,射频传输线包括第一信号线段和第二信号线段；热膨胀系数测试MEMS结构包括待测薄膜组件、梁结构和位移测量结构,待测薄膜组件设置在所述衬底上且与第一信号线段相连,梁结构与待测薄膜组件相连；位移测量结构与第二信号线段相连,且间隔开地位于梁结构的下方；射频测试仪器用于测试热膨胀系数测试MEMS结构的射频隔离度,以最终获得待测薄膜热膨胀系数。本发明可以测得不同材料、连续温度点的、小面积的薄膜的热膨胀系数,通用性好。(The invention discloses a device for testing the thermal expansion coefficient of a thin film material, which comprises a thermal expansion coefficient testing structure, a heating structure and a radio frequency testing instrument. The thermal expansion coefficient test structure comprises a substrate, a radio frequency transmission line and a thermal expansion coefficient test MEMS structure, wherein the radio frequency transmission line comprises a first signal line segment and a second signal line segment; the MEMS structure for testing the thermal expansion coefficient comprises a film component to be tested, a beam structure and a displacement measurement structure, wherein the film component to be tested is arranged on the substrate and is connected with a first signal line segment, and the beam structure is connected with the film component to be tested; the displacement measurement structure is connected with the second signal line segment and is positioned below the beam structure at intervals; the radio frequency test instrument is used for testing the radio frequency isolation of the thermal expansion coefficient test MEMS structure so as to finally obtain the thermal expansion coefficient of the film to be tested. The invention can measure the thermal expansion coefficients of films with different materials, continuous temperature points and small areas, and has good universality.)

1. An apparatus for testing thermal expansion coefficient of thin film material, comprising:

the thermal expansion coefficient test structure comprises a substrate, a radio frequency transmission line and a thermal expansion coefficient test MEMS structure, wherein the radio frequency transmission line is arranged on the upper surface of the substrate and comprises a first signal line segment and a second signal line segment, and the first signal line segment and the second signal line segment are arranged at intervals; the MEMS structure for testing the thermal expansion coefficient comprises a film component to be tested, a beam structure with a longitudinal displacement amplification function and a displacement measurement structure for radio frequency testing, wherein the film component to be tested is arranged on the upper surface of the substrate and connected with the first signal line segment, and the beam structure is connected with the film component to be tested; the displacement measurement structure is connected with the second signal line segment and is positioned below the beam structure at intervals;

a heating structure for heating the CTE testing structure;

and the radio frequency testing instrument is used for connecting with the radio frequency transmission line so as to test the radio frequency isolation of the thermal expansion coefficient testing MEMS structure, and reversely pushing the thermal expansion coefficient of the film to be tested in the film component to be tested through the radio frequency isolation.

2. The apparatus for testing thermal expansion coefficient of thin film material according to claim 1, wherein when the thin film to be tested is a metal thin film, the component to be tested is composed of only the thin film to be tested, the thin film to be tested is directly stacked on the upper surface of the substrate, and the beam structure is connected to the thin film to be tested; when the film to be detected is a non-metal film, the film component to be detected is composed of the film to be detected and a metal functional layer with a known thermal expansion coefficient, the film to be detected and the metal functional layer are stacked on the upper surface of the substrate, the metal functional layer is located below or above the film to be detected, and the beam structure is connected with the metal functional layer.

3. The apparatus for testing thermal expansion coefficient of thin film material according to claim 1, wherein the beam structure is a single-ended clamped beam, and when the beam structure is a single-ended clamped beam, one end of the beam structure is connected to the thin film component to be tested, and the other end of the beam structure is spaced above the displacement measurement structure.

4. The apparatus for testing thermal expansion coefficient of thin film material according to claim 1, wherein the displacement measuring structure is a metal-air-metal capacitor structure.

5. The apparatus for testing thermal expansion coefficient of thin film material as claimed in claim 4, wherein the displacement measuring structure is a series capacitor structure, a parallel capacitor structure or a capacitor network structure composed of a plurality of capacitors.

6. The apparatus for testing thermal expansion coefficient of thin film material according to claim 1, wherein the thermal expansion coefficient testing structure is used for testing the radio frequency performance in a probe station manner or a test board manner.

7. The apparatus for testing thermal expansion coefficient of thin film material as claimed in claim 1, wherein said beam structure is made of conductive metal.

8. The apparatus for testing thermal expansion coefficient of thin film material according to any of claims 1-7, wherein the radio frequency transmission line is a coplanar waveguide transmission line or a microstrip line.

9. The apparatus for testing thermal expansion coefficient of thin film material as claimed in any one of claims 1-7, wherein the heating structure has temperature control and temperature measurement functions.

Technical Field

The invention relates to the technical field of measurement of thermal expansion coefficients of thin film materials, in particular to a device for testing the thermal expansion coefficients of the thin film materials.

Background

Thin film structures are common components in MEMS devices. On one hand, the thermal expansion of the thin film material can be used for designing and manufacturing the actuator based on the thermal drive; on the other hand, thermal stress caused by thermal expansion of the thin film material may cause drift of the device operating point, performance degradation, and even irreversible damage such as device failure. The thermal expansion coefficient of the materials given in some existing technical data is mostly based on the measured results of the bulk materials, and the thin film materials have some deviation from the bulk material performance due to various influencing factors in the growth process.

The predecessors have already carried out some researches on the thermal expansion coefficient of the film material and proposed some test schemes, but most of the tests aim at the film material with the size of the whole wafer, and the measurement is mostly carried out in an optical mode, the average value of the material in the whole wafer is given, and the thermal expansion property of the material in a small range cannot be well represented; there are also some researchers that use MEMS structures to characterize the coefficient of thermal expansion of certain thin film materials, but they are not versatile. Therefore, the method has a very practical significance for providing a universal thin-film material thermal expansion coefficient testing device.

Disclosure of Invention

The present invention is directed to solving at least one of the problems of the prior art. Therefore, an object of the present invention is to provide a device for measuring the thermal expansion coefficient of a thin film material, which can measure the thermal expansion coefficient of thin films with different materials, continuous temperature points and small areas, and has good versatility.

The device for testing the thermal expansion coefficient of the film material comprises:

the thermal expansion coefficient test structure comprises a substrate, a radio frequency transmission line and a thermal expansion coefficient test MEMS structure, wherein the radio frequency transmission line is arranged on the upper surface of the substrate and comprises a first signal line segment and a second signal line segment, and the first signal line segment and the second signal line segment are arranged at intervals; the MEMS structure for testing the thermal expansion coefficient comprises a film component to be tested, a beam structure with a longitudinal displacement amplification function and a displacement measurement structure for radio frequency testing, wherein the film component to be tested is arranged on the upper surface of the substrate and connected with the first signal line segment, and the beam structure is connected with the film component to be tested; the displacement measurement structure is connected with the second signal line segment and is positioned below the beam structure at intervals;

a heating structure for heating the CTE testing structure;

and the radio frequency testing instrument is used for connecting with the radio frequency transmission line so as to test the radio frequency isolation of the thermal expansion coefficient testing MEMS structure, and reversely pushing the thermal expansion coefficient of the film to be tested in the film component to be tested through the radio frequency isolation.

The device for testing the thermal expansion coefficient of the film material provided by the embodiment of the invention has the working principle that: the thermal expansion coefficient testing structure is heated by the heating structure, the temperature of the thermal expansion coefficient testing structure rises after being heated, after the temperature of the film assembly to be tested rises and changes, due to thermal expansion coefficient mismatch, shape change with thick middle edge can be generated, further, the distance between the beam structure and the displacement measuring structure in the up-down direction can be obviously changed, namely, the shape change of the film assembly to be tested amplifies longitudinal displacement (namely, up-down direction displacement) through the beam structure, so that parasitic capacitance of the displacement measuring structure changes, the parasitic capacitance changes are finally reflected to the radio frequency isolation change of the thermal expansion coefficient testing MEMS structure through the radio frequency testing instrument, and the thermal expansion coefficient of the film to be tested in the film assembly to be tested can be reversely deduced through the measurement of the radio frequency isolation.

The device for testing the thermal expansion coefficient of the film material has the following advantages: firstly, the testing device does not aim at specific thin film materials to be tested, can represent different thin film materials to be tested such as metal thin films and nonmetal thin films, and has better universality; secondly, the testing device can measure the thermal expansion coefficient condition in the whole temperature change range instead of a single temperature point value; thirdly, the testing device can test the thin film to be tested with a small area, so that the distribution condition in the surface can be obtained, rather than the average value of the whole surface; fourthly, the testing device utilizes radio frequency characteristics to represent longitudinal displacement, and compared with low-frequency capacitance resistance measurement, the testing device is more accurate.

According to one embodiment of the invention, when the film to be tested is a metal film, the component to be tested is only composed of the film to be tested, the film to be tested is directly stacked on the upper surface of the substrate, and the beam structure is connected with the film to be tested; when the film to be detected is a non-metal film, the film component to be detected is composed of the film to be detected and a metal functional layer with a known thermal expansion coefficient, the film to be detected and the metal functional layer are stacked on the upper surface of the substrate, the metal functional layer is located below or above the film to be detected, and the beam structure is connected with the metal functional layer.

According to one embodiment of the invention, the beam structure is a single-end clamped beam, wherein when the beam structure is the single-end clamped beam, one end of the beam structure is connected with the thin film component to be measured, and the other end of the beam structure is spaced above the displacement measurement structure.

According to one embodiment of the invention, the displacement measuring structure is a metal-air-metal capacitance structure.

According to a further embodiment of the invention, the displacement measuring structure is a series capacitance structure, a parallel capacitance structure or a capacitance network structure consisting of a plurality of capacitances.

According to one embodiment of the invention, the thermal expansion coefficient test structure adopts a probe station mode or a test board mode to carry out radio frequency performance test.

According to one embodiment of the invention, the beam structure is made of a conductive metal.

According to some embodiments of the invention, the radio frequency transmission line is a coplanar waveguide transmission line or a microstrip line.

According to some embodiments of the invention, the heating structure has temperature control and temperature measurement functions.

Additional aspects and advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention.

Drawings

The above and/or additional aspects and advantages of the present invention will become apparent and readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which:

FIG. 1 is a schematic structural diagram of a device for testing the coefficient of thermal expansion of a thin film material according to an embodiment of the present invention.

FIG. 2 is a partially enlarged view of a device for testing the coefficient of thermal expansion of a thin film material according to an embodiment of the present invention.

Fig. 3 is a schematic diagram illustrating a state of a thin film device and a beam structure to be tested before heating in an apparatus for testing a coefficient of thermal expansion of a thin film material according to an embodiment of the present invention.

Fig. 4 is a schematic diagram illustrating a state of a thin film component and a beam structure to be tested after being heated in a testing apparatus for a thermal expansion coefficient of a thin film material according to an embodiment of the present invention.

Fig. 5 is a schematic structural diagram of a thin film device and a beam structure to be tested in a testing apparatus for thermal expansion coefficient of thin film material according to another embodiment of the invention.

Reference numerals:

testing device 1000

Thermal expansion coefficient test structure 1

Substrate 101

First signal line segment 1021 and second signal line segment 1022 of RF transmission line 102

Coefficient of thermal expansion test MEMS structure 103

Test membrane assembly 1031 test membrane 10311 Beam Structure 1032 holes 10321

Displacement measurement structure 1033

Heating structure 2

Radio frequency test instrument 3

Detailed Description

Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the accompanying drawings are illustrative only for the purpose of explaining the present invention, and are not to be construed as limiting the present invention.

The following describes a device 1000 for testing the coefficient of thermal expansion of a thin film material according to an embodiment of the present invention with reference to fig. 1 to 5.

As shown in fig. 1 to 5, the apparatus 1000 for testing the coefficient of thermal expansion of a thin film material according to an embodiment of the present invention includes a thermal expansion coefficient testing structure 1, a heating structure 2, and a radio frequency testing apparatus 3. The thermal expansion coefficient test structure 1 comprises a substrate 101, a radio frequency transmission line 102 and a thermal expansion coefficient test MEMS structure 103, wherein the radio frequency transmission line 102 is arranged on the upper surface of the substrate 101 and comprises a first signal line segment 1021 and a second signal line segment 1022, and the first signal line segment 1021 and the second signal line segment 1022 are arranged at intervals; the MEMS structure 103 for testing thermal expansion coefficient comprises a thin film component 1031 to be tested, a beam structure 1032 with longitudinal displacement amplification function, and a displacement measurement structure 1033 for rf testing, wherein the thin film component 1031 to be tested is disposed on the upper surface of the substrate 101 and connected to the first signal line 1021, and the beam structure 1032 is connected to the thin film component 1031 to be tested; the displacement measurement structure 1033 is connected to the second signal line segment 1022 and is spaced below the beam structure 1032; the heating structure 2 is used for heating the thermal expansion coefficient test structure 1; the radio frequency test instrument 3 is used for connecting with the radio frequency transmission line 102 to test the radio frequency isolation of the MEMS structure 103 by testing the thermal expansion coefficient, and reversely deducing the thermal expansion coefficient of the film 10311 to be tested in the film component 1031 to be tested by the radio frequency isolation.

The device 1000 for testing the coefficient of thermal expansion of the thin film material according to the embodiment of the invention has the working principle that: the heating structure 2 is used for heating the thermal expansion coefficient test structure 1, the temperature of the thermal expansion coefficient test structure 1 rises after being heated, the shape change with thick middle and thin edge can be generated due to thermal expansion coefficient mismatch after the temperature of the thin film component 1031 to be tested changes, and thus the spacing between beam structure 1032 and displacement measurement structure 1033 in the up-down direction can vary significantly (see figures 3 and 4), that is, the shape change of the film assembly 1031 to be measured amplifies the longitudinal displacement (i.e., the up-down displacement) via the beam structure 1032, resulting in the change of the parasitic capacitance of the displacement measurement structure 1033, the parasitic capacitance change is finally reflected to the radio frequency isolation change of the thermal expansion coefficient test MEMS structure 103 by the radio frequency test instrument 3, and through the measurement of the radio frequency isolation, the thermal expansion coefficient of the thin film 10311 to be tested in the thin film assembly 1031 to be tested can be reversely derived.

The device 1000 for testing the coefficient of thermal expansion of the thin film material according to the embodiment of the invention has the following advantages: firstly, the test device 1000 does not aim at a specific material of the thin film 10311 to be tested, can characterize different materials of the thin film 10311 to be tested, such as a metal thin film and a nonmetal thin film, and has good universality; secondly, the testing device 1000 can measure the thermal expansion coefficient condition in the whole temperature variation range, not a single temperature point value; thirdly, the testing device 1000 can test the thin film 10311 to be tested with a small area, so that the distribution condition in the plane can be obtained, rather than the average value of the whole plane; fourthly, the testing device 1000 utilizes radio frequency characteristics to characterize longitudinal displacement, and is more accurate compared with low-frequency capacitance resistance measurement.

According to an embodiment of the present invention, when the film 10311 to be measured is a metal film, the component to be measured is only composed of the film 10311 to be measured, the film 10311 to be measured is directly stacked on the upper surface of the substrate 101 (as shown in fig. 3 and 4) to form a double-layer stacked film structure, the beam structure 1032 is connected to the film 10311 to be measured, the structure is simple, and the shape change of the film component 1031 to be measured when heated can be longitudinally amplified, so that the parasitic capacitance of the displacement measurement structure 1033 is changed; when the film 10311 to be measured is a non-metal film, the film assembly 1031 to be measured is composed of the film 10311 to be measured and the metal functional layer 10312 with a known thermal expansion coefficient, the film 10311 to be measured and the metal functional layer 10312 are stacked on the upper surface of the substrate 101, and the metal functional layer 10312 is located above (as shown in fig. 5) or below the film 10311 to be measured, so as to form a three-layer stacked film structure, the beam structure 1032 is connected with the metal functional layer 10312, the structure is simple, the shape change of the film assembly 1031 to be measured caused by heating can be longitudinally amplified, and further the parasitic capacitance of the displacement measurement structure 1033 is caused to change.

It should be noted that the substrate 101 may be made of silicon, glass or quartz material, and the metal functional layer 10312 with known thermal expansion coefficient should be made of material with good electrical conductivity.

According to an embodiment of the present invention, the beam structure 1032 is a single-ended clamped beam (as shown in fig. 1, 3 and 4), wherein when the beam structure 1032 is a single-ended clamped beam, one end of the beam structure 1032 is connected to the thin film component 1031 to be measured, and the other end of the beam structure 1032 is spaced above the displacement measurement structure 1033. Therefore, the shape change of the film component 1031 to be tested can be effectively amplified by the beam structure 1032 to cause the longitudinal displacement (i.e. the displacement in the up-down direction), so that the parasitic capacitance of the displacement measurement structure 1033 changes, the radio frequency isolation change of the thermal expansion coefficient test MEMS structure 103 can be accurately measured by the radio frequency test instrument 3, and the thermal expansion coefficient of the film material of the layer to be tested can be accurately deduced.

It should be noted that, in some other embodiments, the beam structure 1032 may also be a double-end clamped beam or a multi-end clamped beam, which may be selected according to actual needs.

According to one embodiment of the present invention, displacement measurement structure 1033 is a metal-air-metal capacitive structure. It can be understood that the metal-air-metal capacitor structure is a movable structure, and the capacitance value is easy to change and easy to detect.

According to further embodiments of the present invention, displacement measurement structure 1033 is a series capacitance structure, a parallel capacitance structure, or a capacitance network structure composed of multiple capacitances. It can be understood that the change effect of the parasitic capacitance can be amplified through a series capacitance structure, a parallel capacitance structure or a capacitance network structure consisting of a plurality of capacitors, and the test is more facilitated.

According to an embodiment of the present invention, the cte testing structure 1 performs rf performance testing in a probe station manner or a test board manner. In other words, the cte testing structure 1 can be tested by using a probe station, or the cte testing structure 1 can be fixed and electrically connected to a testing board to be tested by using the testing board, and the cte testing structure 1 is not limited to a specific testing device and is flexible

According to an embodiment of the present invention, the beam structure 1032 is made of a conductive metal, that is, the beam structure 1032 is made of a metal with good conductivity, so as to ensure the accuracy of the measurement result.

Beam structure 1032 is provided with holes 10321 to facilitate MEMS processing, according to an embodiment of the invention.

According to some embodiments of the present invention, the rf transmission line 102 may be a coplanar waveguide transmission line or a microstrip line, etc., according to practical situations.

According to some embodiments of the present invention, the heating structure 2 has temperature control and temperature measurement functions, and can meet the requirement of testing the thermal expansion coefficient of the thin film material. The heating structure 2 may be selected from a heat conduction heating structure 2, a heat convection heating structure 2 or a heat radiation heating structure 2.

As shown in fig. 1 to 4, a specific example of the apparatus 1000 for testing the coefficient of thermal expansion of a film material according to the present invention is described below.

In this particular example, the test apparatus 1000 includes a thermal expansion coefficient test structure 1, a heating structure 2, and a radio frequency test instrument 3.

Specifically, the cte test structure 1 includes a substrate 101, a radio frequency transmission line 102, and a cte test MEMS structure 103. Wherein the substrate 101 is a glass substrate; the radio frequency transmission line 102 is a coplanar waveguide transmission line, the radio frequency transmission line 102 is disposed on the upper surface of the substrate 101 and includes a first signal line segment 1021 and a second signal line segment 1022, and the first signal line segment 1021 and the second signal line segment 1022 are arranged at intervals; the MEMS structure 103 for testing thermal expansion coefficient includes a film component 1031 to be tested, a beam structure 1032 with a longitudinal displacement amplification function, and a displacement measurement structure 1033 for use in a radio frequency test, wherein the film component 1031 to be tested is disposed on the upper surface of the substrate 101, the film component 1031 to be tested is only composed of a film 10311 to be tested, the film 10311 to be tested is a metal film, and the film 10311 to be tested is directly stacked on the upper surface of the substrate 101 and connected to the first signal line segment 1021; the beam structure 1032 is made of conductive metal and has a hole 10321, and one end of the beam structure 1032 is connected to the film 10311 to be measured; the displacement measurement structure 1033 is a metal-air-metal capacitor structure, which is a series capacitor structure, and meanwhile, a probe station mode or a test board mode can be adopted for radio frequency performance test, the displacement measurement structure 1033 is connected with the second signal line segment 1022, and the other end of the displacement measurement structure 1033 is spaced below the beam structure 1032.

The thermal expansion coefficient test structure 1 is arranged on a heating structure 2, and the heating structure 2 is used for heating the thermal expansion coefficient test structure 1.

The radio frequency test instrument 3 is used for connecting with the radio frequency transmission line 102 to test the radio frequency isolation of the MEMS structure 103 by testing the thermal expansion coefficient, and reversely deducing the thermal expansion coefficient of the film 10311 to be tested in the film component 1031 to be tested 1031 through the radio frequency isolation.

The testing device 1000 has the following advantages: firstly, the testing device 1000 does not aim at a specific to-be-tested thin film 10311 material, can characterize the to-be-tested metal thin film material, and has better universality; secondly, the testing device 1000 can measure the thermal expansion coefficient condition in the whole temperature variation range, not a single temperature point value; thirdly, the testing device 1000 can test the thin film 10311 to be tested with a small area, so that the distribution condition in the plane can be obtained, rather than the average value of the whole plane; fourthly, the testing device 1000 utilizes radio frequency characteristics to characterize longitudinal displacement, and is more accurate compared with low-frequency capacitance resistance measurement.

While embodiments of the invention have been shown and described, it will be understood by those of ordinary skill in the art that: various changes, modifications, substitutions and alterations can be made to the embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.