Method for measuring thermal expansion coefficient of metal in mixed bonding sample by using atomic force microscope heating module

Abstract

The invention relates to a method for measuring the thermal expansion coefficient of metal in a mixed bonding sample by using an atomic force microscope heating module. The method comprises the following steps: constructing a heating platform on an atomic force microscope; scanning the metal-dielectric sample at normal temperature to obtain initial morphology data; carrying out gradient heating on the metal-dielectric sample and carrying out surface topography characterization; processing scanning data of the atomic force microscope; and based on the obtained initial morphology data and the extracted relative morphology change information, calculating a thermal expansion coefficient [delta] [alpha] of the metal relative to the dielectric medium through a thermal expansion model. Compared with the prior art, the method can accurately calculate the thermal expansion coefficient of the metal relative to the dielectric so as to meet the requirement for accurate control of the thermal expansion behavior of the metal and the dielectric in the hybrid bonding technology, and then the height of the metal relative to the dielectric in the CMP process in hybrid bonding is controlled. The reliability of a bonding interface and the performance of a semiconductor device can be improved.

Description

Technical Field

[0001] The present invention relates to the technical field of integrated circuit three-dimensional packaging, and in particular to a method for measuring the thermal expansion coefficient of metal in a hybrid bonded sample by utilizing an atomic force microscope heating module. Background Art

[0002] In hybrid bonding technology for integrated circuit 3D packaging, metal is a key interconnect material, and its thermal expansion behavior has a significant impact on the reliability of the bonding interface. Hybrid bonding technology requires that metal and dielectrics be tightly bonded to achieve electrical connection and mechanical support between chips. However, due to the large gap between the coefficient of thermal expansion (CTE) of metal and the CTE of dielectrics, during high-temperature bonding, the expansion of the metal may lead to stress concentration at the bonding interface, and even cause failure problems such as delamination or cracking. These problems seriously affect the performance and life of semiconductor devices, so it is crucial to accurately measure and understand the thermal expansion behavior of metals during the hybrid bonding process.

[0003] Currently, researchers are trying to use different techniques to measure the thermal expansion coefficient of thin films or solid materials. For example, document CN112986320A proposes a method for measuring the thermal expansion coefficient of thin films. This method prepares a step-like structure on the surface of the film to be measured and uses an atomic force microscope or a nanoindenter to detect the change in film thickness at different temperatures. This method is suitable for thin film materials that are difficult to peel off from the substrate, such as low-k films on silicon substrates. However, this method mainly focuses on the measurement of the thermal expansion coefficient of thin film materials, does not consider the relative thermal expansion behavior between metals and dielectrics, and does not provide a solution for measurement in an oxygen-free environment.

[0004] Document CN118130532A discloses a method for testing the thermal expansion response of solid-state materials based on atomic force microscopy. This method involves placing the thermal probe of an atomic force microscope in contact with the solid-state material and applying AC excitation to induce thermal expansion. Although this method can measure the thermal expansion response of solid-state materials, it is mainly aimed at inorganic solid-state electrolyte materials and does not specifically involve the determination of the relative thermal expansion coefficient between metals and dielectrics. Moreover, the method does not explicitly mention how to perform measurements in an oxygen-free environment to prevent the influence of metal oxidation on the measurement results.

[0005] In summary, the existing technology has the following main problems:

[0006] There is a lack of effective methods for measuring the relative thermal expansion behavior between metals and dielectrics in hybrid bonding technology. Existing technologies often focus on determining the thermal expansion coefficient of a single material (such as thin films or inorganic solid electrolytes), but fail to fully consider the interaction between metals and dielectrics and accurately measure the relative thermal expansion coefficient.

[0007] During the measurement process, it is difficult to avoid the influence of metal oxidation on the measurement results. Especially in high temperature environments, metal oxidation will cause distortion of the measurement data and fail to accurately reflect the actual thermal expansion behavior of the metal. Summary of the Invention

[0008] The purpose of the present invention is to overcome the defects of the above-mentioned existing technologies and provide a method for measuring the thermal expansion coefficient of metal in hybrid bonding samples using an atomic force microscope heating module. The method can accurately calculate the thermal expansion coefficient of metal relative to dielectric, so as to meet the demand for precise control of the thermal expansion behavior of metal and dielectric in hybrid bonding technology, and then control the height of metal relative to dielectric in the CMP process in hybrid bonding, which can improve the reliability of the bonding interface and the performance of semiconductor devices.

[0009] The purpose of the present invention can be achieved by the following technical solutions:

[0010] The present invention provides a method for measuring the thermal expansion coefficient of metal in a hybrid bonded sample using an atomic force microscope heating module, which is characterized by comprising the following steps:

[0011] S1. Build a heating mechanical platform on an atomic force microscope;

[0012] S2. Based on the heating mechanics platform built in S1, scan the metal-dielectric sample at room temperature to obtain initial morphological data;

[0013] S3. Using the heating mechanics platform built in S1, the metal-dielectric sample is subjected to gradient heating in an oxygen-free environment, and the surface morphology is characterized in real time during the heating process.

[0014] S4. Processing the gradient heating related data and the data obtained from the morphology characterization in S3 to extract information on relative morphology changes between the metal and the dielectric;

[0015] S5. Based on the initial morphology data obtained in S2 and the relative morphology change information extracted in S4, the thermal expansion coefficient Δα of the metal relative to the dielectric is calculated using a thermal expansion model.

[0016] Furthermore, S1 specifically includes the following steps:

[0017] After the probe is loaded on the ceramic heated probe holder, the ceramic heated probe holder is mounted on the AFM scanner and the laser is adjusted to the probe using the shadow method;

[0018] Call up the heated sample stage, close the AFM scanning control software and power off, load the pressurized thermocouple, and then reopen the AFM scanning control software;

[0019] Mount the annular gas channel on a heated sample stage;

[0020] Fix the sample to the sample plate with thermally conductive adhesive and place it on the magnetic surface of the pressurized thermocouple;

[0021] Assemble and turn on the fluid cooling system and heat application controller.

[0022] Furthermore, in S1, the probe is a probe without metal coating.

[0023] Furthermore, in S1, the specific steps also include:

[0024] The annular gas channel is installed on the heated sample stage to introduce inert or reducing gas during heating to create an oxygen-free environment to prevent metal oxidation.

[0025] Furthermore, S2 specifically includes the following steps:

[0026] Under normal temperature, set the scanning parameters of the atomic force microscope, including scanning range, resolution and scanning rate;

[0027] Bring the probe close to the surface of the metal-dielectric sample and start scanning;

[0028] Record and save the initial topography data obtained by scanning, including the height information of the metal area and the dielectric area.

[0029] Furthermore, S3 specifically includes the following steps:

[0030] Set the temperature gradient and gradually heat the sample from room temperature to multiple target temperature points in an oxygen-free environment;

[0031] Maintain constant temperature for a preset time at each target temperature point to ensure uniform sample temperature;

[0032] Under constant temperature, the atomic force microscope is used to scan the surface of the sample and record the morphological data at different temperatures;

[0033] After completing heating and scanning at all temperature points, turn off the heating module and allow the sample to cool naturally to room temperature.

[0034] Furthermore, S4 specifically includes the following steps:

[0035] Preprocessing the scan data acquired in S3, wherein the preprocessing includes removing noise and correcting data drift;

[0036] Perform plane fitting on the pre-processed data to eliminate the influence of the tilt of the probe scanning process on the measurement results;

[0037] Use cross-section analysis tools to extract height difference data between the metal area and the surrounding dielectric area;

[0038] The extracted height difference data is compared and analyzed with the initial morphology data obtained in step S2 to calculate the relative morphology changes of the metal and the dielectric at different temperatures.

[0039] Furthermore, S5 specifically includes the following steps:

[0040] Substitute the relative morphological changes of the metal and dielectric extracted in step S4 into the calculation formula of the thermal expansion model:

[0041] Δl=(l+2dν)ΔαΔT;

[0042] Where Δl is the total deformation of the metal during thermal expansion, ν is the Poisson's ratio of the metal, l is the initial height of the metal via, d is the diameter of the metal via, Δα is the thermal expansion coefficient of the metal and dielectric, and ΔT is the temperature change;

[0043] The calculation formula of the thermal expansion model is solved to obtain the thermal expansion coefficient Δα of the metal relative to the dielectric.

[0044] Furthermore, in S5, the process of obtaining various parameters in the thermal expansion model specifically includes:

[0045] measuring an initial height l of the metal via and a diameter d of the metal via from the initial topography data acquired in S2;

[0046] Obtain the Poisson's ratio ν of the metal based on the known properties of the metal material or by querying the material database;

[0047] Determine the temperature change ΔT from the temperature data recorded during the gradient heating process of S3;

[0048] Δl is obtained by comparing the relative morphological changes of metal and dielectric at different temperatures in S4.

[0049] Furthermore, the specific process of measuring the initial height l and the diameter d of the metal through hole from the initial topography data obtained in S2 includes:

[0050] Open the initial topography data in the AFM analysis software;

[0051] Extract geometric features of metal through-hole areas based on topography data analysis tools;

[0052] The height analysis function measures the height difference between the top of the metal via and the substrate dielectric to determine the initial height l of the metal via.

[0053] Use a diameter measuring tool to measure the diameter d of the metal through hole at its opening.

[0054] Furthermore, the specific process of obtaining Δl by comparing the relative morphological changes of the metal and the dielectric at different temperatures in S4 includes:

[0055] Positionally align the topography data obtained by scanning at different temperatures with the topography data at the initial temperature in the same spatial coordinate system;

[0056] Mark multiple measurement points at the center of the metal through hole and the surrounding dielectric area;

[0057] Using the cross-sectional analysis function of the atomic force microscope software, the height difference between the metal surface and the dielectric surface at the same point in the vertical direction is measured and recorded;

[0058] The metal-dielectric height difference at the initial temperature is used as a benchmark;

[0059] The reference value is subtracted from the height difference at each target temperature to obtain multiple Δl values.

[0060] Compared with the prior art, the present invention has the following beneficial effects:

[0061] 1) The present invention addresses the critical issue of bonding interface failure caused by differences in the thermal expansion coefficients of metals and dielectrics in hybrid bonding technology. Existing technologies, such as the thin film thermal expansion coefficient determination method (CN112986320A) and the solid-state material thermal expansion response test method (CN118130532A), have limitations such as not considering the relative thermal expansion behavior of metals and dielectrics and not providing an oxygen-free environment measurement solution. The present invention utilizes an atomic force microscope heating module to gradient heat and characterize metal-dielectric samples in an oxygen-free environment in real time, effectively avoiding interference from metal oxidation. Combined with a thermal expansion model, the relative thermal expansion coefficient is accurately calculated, providing key data support for controlling the height of metals and dielectrics in hybrid bonding.

[0062] 2) The present invention also has high-precision in-situ characterization and real-time data analysis capabilities. From the detection process point of view, with the help of the high-resolution scanning function of the atomic force microscope, the in-situ micromorphology monitoring of the metal-dielectric interface is realized, and the height change of the metal relative to the dielectric at different temperatures is accurately captured. Its measurement accuracy can reach the nanometer level, far exceeding traditional macroscopic measurement methods. In data processing, through plane fitting, cross-section analysis and other methods, the height information of the metal area is efficiently extracted, and the thermal expansion coefficient is quickly calculated using the thermal expansion model. The whole process has a high degree of automation, and it is completed in one stop from heating to data analysis, which significantly improves the measurement efficiency while ensuring the accuracy and reliability of the results, effectively ensuring the quality control of the hybrid bonding interface in semiconductor manufacturing. BRIEF DESCRIPTION OF THE DRAWINGS

[0063] Figure 1This is a flow chart of the present invention for measuring the thermal expansion coefficient of metal in a hybrid bonded sample using an atomic force microscope heating module;

[0064] Figure 2 This is the copper-silicon dioxide morphology measurement image at room temperature in the application example;

[0065] Figure 3 This is the copper-silicon dioxide morphology measurement image under gradient temperature increase in the application example;

[0066] Figure 4 This is a copper-silicon dioxide height analysis diagram at different temperatures in the application example. DETAILED DESCRIPTION

[0067] The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments. Component models, material names, connection structures, control methods, algorithms, and other features not explicitly described in this technical solution are considered common technical features disclosed in the prior art.

[0068] Example 1

[0069] In this embodiment, the thermal expansion coefficient of metal in a hybrid bonded sample is measured using an atomic force microscope heating module. For a flow chart, see Figure 1 , including the following steps:

[0070] Step 1: Build a heating mechanical platform on the atomic force microscope;

[0071] In the specific implementation, in step 1, a heating module is built on the atomic force microscope. The specific steps include:

[0072] 11) After the probe is loaded onto the ceramic heated probe holder, the ceramic heated probe holder is loaded onto the atomic force microscope scanner, and the laser is adjusted to hit the probe using the shadow method;

[0073] 12) Open the heated sample stage, close the AFM scanning control software, ensure that the power is off, install the pressurized thermocouple, and then open the software;

[0074] 13) Mount the annular gas channel on the heated sample stage;

[0075] 14) Fix the sample on the sample plate with thermally conductive adhesive and place it on the magnetic surface of the pressurized thermocouple;

[0076] 15) Assemble the fluid cooling system and heat application controller and turn on the switch.

[0077] In specific implementation, in step 1, the probe in 11) is a probe without metal coating.

[0078] Step 2: Scan the metal-dielectric sample at room temperature to obtain initial morphology data;

[0079] Step 3, gradient heating the metal-dielectric sample and characterizing the surface morphology;

[0080] Step 4: Processing the AFM scanning data;

[0081] Step 5: Based on the thermal expansion model, calculate the thermal expansion coefficient Δα of the metal relative to the dielectric using the following formula: Δl = Δl thermal expansion + Δl thermal strain = Δlz + ν(Δlx + Δly) = lΔαΔT + 2dνΔαΔT = (l + 2dν)ΔαΔT.

[0082] In specific implementation, in step 2, the surface morphology of the hybrid bonded sample is measured at room temperature. The specific steps include: at room temperature, after setting appropriate scanning parameters, scanning the sample surface including the metal-dielectric area to obtain initial surface morphology data.

[0083] In specific implementation, in step three, the mixed bonded sample is subjected to gradient heating and the morphology is characterized. The specific steps include: heating the sample in sections by setting the temperature gradient, and measuring the surface morphology after maintaining a constant temperature in each target temperature section for a predetermined time; after completing the characterization of the highest temperature node, cooling to ambient temperature, and maintaining a constant temperature for a predetermined time, performing surface morphology characterization again.

[0084] In specific implementation, in step three, during the entire process of heating and measuring, one or more inert gases or reducing gases are continuously introduced to the sample surface through the annular gas channel to inhibit oxidation of the metal surface during heating.

[0085] In specific implementation, in step three, the flow rate of the introduced gas needs to be controlled to ensure that the sample is heated in a completely oxygen-free environment.

[0086] In specific implementation, in step 4, data processing is performed on the characterization results of step 3. The specific steps include:

[0087] After plane fitting processing of the scanned image in the atomic force microscope data processing software, the height of the metal area relative to the surrounding dielectric was obtained through cross-sectional analysis, and the height changes of the metal relative to the dielectric at different temperatures were compared.

[0088] In a specific implementation, in step five, the thermal expansion coefficient of the metal in the hybrid bonding sample is calculated, and the height of the metal relative to the dielectric at different temperatures obtained in step four is substituted into the formula: Δl=Δl thermal expansion+Δlthermal strain=Δlz+ν(Δlx+Δly)=lΔαΔT+2dνΔαΔT=(l+2dν)ΔαΔT, and the thermal expansion coefficient mismatch value Δα of the metal relative to the dielectric is calculated, where Δlx, Δly and Δlz are the expansions on the x-axis, y-axis and z-axis respectively; ν is the Poisson's ratio of the metal; l is the initial height of the metal through hole, d is the diameter of the metal through hole, and Δα is the thermal expansion coefficient mismatch value of the metal relative to the dielectric (α 金属 -α 电介质 ), which is the thermal expansion coefficient of the metal relative to the dielectric, Δα.

[0089] In a specific implementation, the specific process of measuring the initial height l and the diameter d of the metal through hole in the acquired initial topography data includes:

[0090] Open the initial topography data in the AFM analysis software;

[0091] Extract geometric features of metal through-hole areas based on topography data analysis tools;

[0092] The height analysis function measures the height difference between the top of the metal via and the substrate dielectric to determine the initial height l of the metal via.

[0093] Use a diameter measuring tool to measure the diameter d of the metal through hole at its opening.

[0094] In the specific implementation, step five includes the following steps:

[0095] Substitute the extracted relative morphological changes of metal and dielectric into the calculation formula of the thermal expansion model:

[0096] Δl=(l+2dν)ΔαΔT;

[0097] Where Δl is the total deformation of the metal during thermal expansion, ν is the Poisson's ratio of the metal, l is the initial height of the metal via, d is the diameter of the metal via, Δα is the thermal expansion coefficient of the metal and dielectric, and ΔT is the temperature change;

[0098] The calculation formula of the thermal expansion model is solved to obtain the thermal expansion coefficient Δα of the metal relative to the dielectric.

[0099] The process of obtaining the various parameters in the thermal expansion model specifically includes:

[0100] measuring an initial height l of the metal via and a diameter d of the metal via from the initial topography data acquired in S2;

[0101] Obtain the Poisson's ratio ν of the metal based on the known properties of the metal material or by querying the material database;

[0102] Determine the temperature change ΔT from the temperature data recorded during the gradient heating process of S3;

[0103] Δl is obtained by comparing the relative morphological changes of metal and dielectric at different temperatures in S4.

[0104] In a specific implementation, the specific process of measuring the initial height l and the diameter d of the metal through hole from the initial topography data obtained in S2 includes:

[0105] Open the initial topography data in the AFM analysis software;

[0106] Extract geometric features of metal through-hole areas based on topography data analysis tools;

[0107] The height analysis function measures the height difference between the top of the metal via and the substrate dielectric to determine the initial height l of the metal via.

[0108] Use a diameter measuring tool to measure the diameter d of the metal through hole at its opening.

[0109] In a specific implementation, the specific process of obtaining Δl by comparing the relative morphological changes of the metal and the dielectric at different temperatures in S4 includes:

[0110] Positionally align the topography data obtained by scanning at different temperatures with the topography data at the initial temperature in the same spatial coordinate system;

[0111] Mark multiple measurement points at the center of the metal through hole and the surrounding dielectric area;

[0112] Using the cross-sectional analysis function of the atomic force microscope software, the height difference between the metal surface and the dielectric surface at the same point in the vertical direction is measured and recorded;

[0113] The metal-dielectric height difference at the initial temperature is used as a benchmark;

[0114] Subtracting the reference value from the altitude difference at each target temperature yields multiple Δl values, which are used to calculate Δα.

[0115] Specifically, the present embodiment scheme realizes the oxygen-free environment heating and morphological characterization of the metal-dielectric sample by the atomic force microscope heating module. Its core mechanism is to accurately control the gas environment during the heating process and monitor the surface morphology changes of the sample in real time. During the heating process, the annular gas channel is loaded on the heated sample stage, and a high-purity inert gas (such as nitrogen) or reducing gas is introduced into it to replace the original air around the sample and construct an oxygen-free measurement environment. This oxygen-free environment effectively isolates the contact between oxygen and the metal sample, fundamentally preventing the oxidation reaction of the metal at high temperature and ensuring the chemical stability of the metal sample during the heating process. At the same time, the probe of the atomic force microscope scans the sample surface with extremely high resolution. During the heating process, the metal and the dielectric produce different morphological changes due to the difference in thermal expansion coefficient. The probe can capture these tiny changes in real time and convert them into electrical signals. After subsequent data processing and analysis, these signals can obtain the relative morphological change information of the metal and the dielectric at different temperatures, providing basic data support for the accurate calculation of the thermal expansion coefficient.

[0116] Specifically, this embodiment calculates the thermal expansion coefficient Δα of the metal relative to the dielectric based on the thermal expansion model. The construction of this model is derived from the physical law of thermal expansion of the material. When the material is heated, the thermal motion of the atoms or molecules inside it is enhanced, causing the volume of the material to expand. For a composite structure composed of metal and dielectric, when the temperature changes ΔT, the thermal expansion behavior of the metal can be described from two dimensions: axial and lateral. Axial thermal expansion is mainly manifested as the height change Δlz of the metal through-hole in the vertical direction (z-axis), which is due to the accumulation of thermal motion displacement of metal atoms in the vertical direction; lateral thermal expansion is manifested as the volume expansion of the metal in the horizontal plane (x-axis and y-axis direction), which is affected by the Poisson's ratio ν of the metal. The Poisson's ratio reflects the ratio of the lateral strain to the longitudinal strain of the material when it is subjected to lateral force. According to the thermal expansion model formula Δl = Δl thermal expansion + Δl thermal strain = Δlz + ν(Δlx + Δly) = lΔαΔT + 2dνΔαΔT = (l + 2dν)ΔαΔT, where l is the initial height of the metal via and d is the diameter of the metal via. By processing the atomic force microscope scanning data, the height change Δl of the metal relative to the dielectric can be obtained. Combined with the known initial geometric parameters l and d, as well as the Poisson's ratio ν of the metal (which can be queried through a material database or experimentally determined), the thermal expansion coefficient mismatch value Δα of the metal relative to the dielectric (i.e., the thermal expansion coefficient Δα of the metal relative to the dielectric required to be calculated in the present invention) can be solved. This model calculation process takes into account the interaction between the metal and the dielectric and the influence of geometric dimensions on thermal expansion, thereby achieving accurate quantification of the metal's thermal expansion coefficient, providing a key theoretical basis and data support for the height control of the metal and dielectric in hybrid bonding technology.

[0117] Application Example 1

[0118] This embodiment provides a method for measuring the thermal expansion coefficient of metal in a hybrid bonded sample using an atomic force microscope heating module, comprising the following steps:

[0119] Step 1: Build a heating mechanical platform on the atomic force microscope;

[0120] In step one, include:

[0121] 11) After the probe is loaded onto the ceramic heated probe holder, the ceramic heated probe holder is loaded onto the atomic force microscope scanner, and the laser is adjusted to hit the probe using the shadow method;

[0122] The probe is a probe without metal coating;

[0123] 12) Open the heated sample stage, close the AFM scanning control software, ensure that the power is off, install the pressurized thermocouple, and then open the software;

[0124] 13) Mount the annular gas channel on the heated sample stage;

[0125] 14) Fix the sample on the sample plate with thermally conductive double-sided tape and place it on the magnetic surface of the pressurized thermocouple;

[0126] 15) Assemble the fluid cooling system and heat application controller and turn on the switch.

[0127] Step 2: Scan the copper-silicon dioxide sample at room temperature to obtain initial morphology data;

[0128] At 25 °C, the resolution was set to 512 × 512 and the scanning rate was set to 1 Hz. The surface area of ​​the copper-silicon dioxide sample was scanned to obtain the initial surface morphology data, such as Figure 2 shown.

[0129] Step 3, performing gradient heating on the copper-silicon dioxide sample and characterizing the surface morphology;

[0130] The copper-silicon dioxide sample was heated to 100°C, 150°C and 200°C in sections at a heating rate of 50°C-75°C / time. After each heating period, the temperature was kept constant at ±0.1°C for 10 minutes before surface morphology measurement was performed. After the copper-silicon dioxide sample was heated to 200°C for characterization, it was cooled to room temperature and kept constant at ±0.1°C for 10 minutes before the surface morphology of the copper-silicon dioxide sample was characterized again. Figure 3 Shown are atomic force microscope morphologies at 100°C (upper left), 150°C (upper right), 200°C (lower left), and finally cooled to room temperature (lower right).

[0131] During the entire heating and measurement process, nitrogen gas was continuously introduced to the sample surface through the annular gas channel to inhibit oxidation of the copper surface during heating. The flow rate of the nitrogen gas was controlled at 50 mL / min.

[0132] Step 4: Processing the AFM scanning data;

[0133] After plane fitting processing of the scanned image in the atomic force microscope data processing software, the height of the copper area relative to the surrounding silicon dioxide is obtained through cross-sectional analysis, and the height changes of copper relative to silicon dioxide at different temperatures are compared, such as Figure 4 Shown is a schematic diagram of the copper-silicon dioxide cross-section height at different temperatures.

[0134] Step 5: Based on the thermal expansion model, calculate the linear thermal expansion coefficient formula using the following formula: α = ΔL / (L0*ΔT), where ΔL is the change in length, L0 is the initial length, and ΔT is the temperature change.

[0135] Substitute the height of copper relative to the silicon dioxide dielectric at different temperatures obtained in step 4 into the formula: Δl = Δl thermal expansion + Δl thermal strain = Δlz + ν (Δlx + Δly)

[0136] = lΔαΔT + 2dνΔαΔT = (l + 2dν)ΔαΔT, calculating the thermal expansion coefficient mismatch Δα between copper and silicon dioxide. From 25°C to 100°C, Δl is approximately 10 nm, and Δα is approximately 43.9 ppm / °C; from 100°C to 150°C, Δl is approximately 10 nm, and Δα is approximately 65.8 ppm / °C; from 150°C to 200°C, Δl is approximately 30 nm, and Δα is approximately 197 ppm / °C.

[0137] The above description of the embodiments is intended to facilitate understanding and use of the invention by those skilled in the art. It will be apparent that those skilled in the art can readily make various modifications to these embodiments and apply the general principles described herein to other embodiments without requiring inventive effort. Therefore, the present invention is not limited to the above-described embodiments. Improvements and modifications made by those skilled in the art based on the disclosure of the present invention, without departing from the scope of the present invention, should be within the scope of protection of the present invention.

Claims

1. A method for measuring the thermal expansion coefficient of metal in a hybrid bonded sample using an atomic force microscope heating module, characterized in that: The following steps are involved: S1. Build a heating mechanical platform on an atomic force microscope; S2. Based on the heating mechanics platform built in S1, scan the metal-dielectric sample at room temperature to obtain initial morphological data; S3. Using the heating mechanics platform built in S1, the metal-dielectric sample is subjected to gradient heating in an oxygen-free environment, and the surface morphology is characterized in real time during the heating process. S4. Processing the gradient heating related data and the data obtained from the morphology characterization in S3 to extract information on relative morphology changes between the metal and the dielectric; S5. Based on the initial morphology data obtained in S2 and the relative morphology change information extracted in S4, the thermal expansion coefficient Δα of the metal relative to the dielectric is calculated using a thermal expansion model.

2. The method for measuring the thermal expansion coefficient of metal in a hybrid bonded sample using an atomic force microscope heating module according to claim 1, characterized in that: S1 specifically includes the following steps: After the probe is loaded on the ceramic heated probe holder, the ceramic heated probe holder is mounted on the AFM scanner and the laser is adjusted to the probe using the shadow method; Call up the heated sample stage, close the AFM scanning control software and power off, load the pressurized thermocouple, and then reopen the AFM scanning control software; Mount the annular gas channel on a heated sample stage; Fix the sample to the sample plate with thermally conductive adhesive and place it on the magnetic surface of the pressurized thermocouple; Assemble and turn on the fluid cooling system and heat application controller.

3. The method for measuring the thermal expansion coefficient of metal in a hybrid bonded sample using an atomic force microscope heating module according to claim 2, characterized in that: In S1, the probe is a probe without metal coating.

4. The method for measuring the thermal expansion coefficient of metal in a hybrid bonded sample using an atomic force microscope heating module according to claim 1, wherein: S2 specifically includes the following steps: Under normal temperature, set the scanning parameters of the atomic force microscope, including scanning range, resolution and scanning rate; Bring the probe close to the surface of the metal-dielectric sample and start scanning; Record and save the initial topography data obtained by scanning, including the height information of the metal area and the dielectric area.

5. The method for measuring the thermal expansion coefficient of metal in a hybrid bonded sample using an atomic force microscope heating module according to claim 1, characterized in that: In S3, the following steps are specifically included: Set the temperature gradient and gradually heat the sample from room temperature to multiple target temperature points in an oxygen-free environment; Maintain constant temperature for a preset time at each target temperature point to ensure uniform sample temperature; Under constant temperature, the atomic force microscope is used to scan the surface of the sample and record the morphological data at different temperatures; After completing heating and scanning at all temperature points, turn off the heating module and allow the sample to cool naturally to room temperature.

6. The method for measuring the thermal expansion coefficient of metal in a hybrid bonded sample using an atomic force microscope heating module according to claim 1, characterized in that: S4 specifically includes the following steps: Preprocessing the scan data acquired in S3, wherein the preprocessing includes removing noise and correcting data drift; Perform plane fitting on the pre-processed data to eliminate the influence of the tilt of the probe scanning process on the measurement results; Use cross-section analysis tools to extract height difference data between the metal area and the surrounding dielectric area; The extracted height difference data is compared and analyzed with the initial morphology data obtained in step S2 to calculate the relative morphology changes of the metal and the dielectric at different temperatures.

7. The method for measuring the thermal expansion coefficient of metal in a hybrid bonded sample using an atomic force microscope heating module according to claim 1, characterized in that: S5 specifically includes the following steps: Substitute the relative morphological changes of the metal and dielectric extracted in step S4 into the calculation formula of the thermal expansion model: Δl=(l+2dν)ΔαΔT; Where Δl is the total deformation of the metal during thermal expansion, ν is the Poisson's ratio of the metal, l is the initial height of the metal via, d is the diameter of the metal via, Δα is the thermal expansion coefficient of the metal and dielectric, and ΔT is the temperature change; The calculation formula of the thermal expansion model is solved to obtain the thermal expansion coefficient Δα of the metal relative to the dielectric.

8. The method for measuring the thermal expansion coefficient of metal in a hybrid bonded sample using an atomic force microscope heating module according to claim 7, characterized in that: In S5, the process of obtaining various parameters in the thermal expansion model specifically includes: measuring an initial height l of the metal via and a diameter d of the metal via from the initial topography data acquired in S2; Obtain the Poisson's ratio ν of the metal based on the known properties of the metal material or by querying the material database; Determine the temperature change ΔT from the temperature data recorded during the gradient heating process of S3; Δl is obtained by comparing the relative morphological changes of metal and dielectric at different temperatures in S4.

9. The method for measuring the thermal expansion coefficient of metal in a hybrid bonded sample using an atomic force microscope heating module according to claim 8, characterized in that: The specific process of measuring the initial height l and the diameter d of the metal through hole from the initial topography data obtained by S2 includes: Open the initial topography data in the AFM analysis software; Extract geometric features of metal through-hole areas based on topography data analysis tools; The height analysis function measures the height difference between the top of the metal via and the substrate dielectric to determine the initial height l of the metal via. Use a diameter measuring tool to measure the diameter d of the metal through hole at its opening.

10. The method for measuring the thermal expansion coefficient of metal in a hybrid bonded sample using an atomic force microscope heating module according to claim 8, characterized in that: The specific process of obtaining Δl by comparing the relative morphological changes of metal and dielectric at different temperatures in S4 includes: Positionally align the topography data obtained by scanning at different temperatures with the topography data at the initial temperature in the same spatial coordinate system; Mark multiple measurement points at the center of the metal through hole and the surrounding dielectric area; Using the cross-sectional analysis function of the atomic force microscope software, the height difference between the metal surface and the dielectric surface at the same point in the vertical direction is measured and recorded; The metal-dielectric height difference at the initial temperature is used as a benchmark; The reference value is subtracted from the height difference at each target temperature to obtain multiple Δl values.

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