Wafer level package chip x-ray imaging in-situ heating characterization device

Abstract

The application relates to a wafer-level package chip X-ray imaging in-situ heating characterization device, which comprises a rotating platform and a sample bin arranged on the rotating platform, a wafer to be tested is arranged in the sample bin; a bin cover, which comprises a bin cover main body, an infrared heating plate and a non-contact temperature probe, the infrared heating plate is arranged on the bin cover main body and is arranged towards the sample bin, the infrared heating plate and the wafer to be tested are arranged in parallel and the centers of the infrared heating plate and the wafer to be tested are aligned, the non-contact temperature probe is arranged on the bin cover main body and is used for detecting the temperature of the infrared heating plate in the sample bin; an infrared heating temperature controller, which is connected with the infrared heating plate and the non-contact temperature probe respectively and is configured to adjust the power of the infrared heating plate according to the temperature value collected by the non-contact temperature probe; and a 4D X-ray CT detector, which is used for scanning the wafer to be tested for detection. Compared with the prior art, the application can realize accurate in-situ thermal failure test on eight to twelve inch large-size wafer-level package chips.

Description

Technical Field

[0001] This invention relates to the field of chip packaging and testing, and in particular to a wafer-level packaged chip X-ray imaging in-situ heating characterization device. Background Technology

[0002] As integrated circuits (ICs) become increasingly miniaturized and denser, the thermodynamic behavior of their internal structures under high-temperature operating environments (such as material expansion, solder joint fracture, and interlayer debonding) has an increasingly critical impact on reliability. For example, the literature "Thermal-Mechanical Characterization of Wafer Level Packaging Technologies" discloses a detection scheme for the thermodynamic behavior of wafers. However, traditional detection methods, including the aforementioned literature (such as slicing SEM and infrared thermography), have limitations such as being destructive and unable to dynamically observe the evolution of internal three-dimensional defects.

[0003] While dynamic non-destructive testing has been achieved in other fields, such as materials science and biomedicine, by introducing 4D X-ray CT technology, the inventors discovered some shortcomings when attempting to introduce in-situ wafer inspection, as follows:

[0004] 1. In the in-situ thermal failure characterization of large-size wafer-level packaged chips ranging from eight to twelve inches, the thermal gradient within the wafer plane is too high, making it difficult to meet the stringent requirements of advanced packaging processes for heating temperature uniformity.

[0005] 2. The strong X-ray scattering noise of metal heating elements can mask the structural evolution of micron-level solder joints or vias inside the chip, making it difficult to directly observe the internal failure dynamics of the packaged chip under real high-temperature conditions, which seriously restricts the reliability optimization process of high-density electronic devices.

[0006] Therefore, those skilled in the art urgently desire a solution that can achieve accurate in-situ thermal failure testing for large-size wafer-level packaged chips ranging from eight to twelve inches. Summary of the Invention

[0007] The purpose of this invention is to provide a wafer-level packaged chip X-ray imaging in-situ heating characterization device. By designing an infrared heating plate for heating, on the one hand, it can solve the problem of excessively high thermal gradient in the wafer plane and meet the stringent requirements of advanced packaging processes for heating temperature uniformity. On the other hand, it will not generate strong X-ray scattering noise that obscures the structural evolution of micron-level solder joints or vias inside the chip, and can directly observe the internal failure dynamics of the packaged chip under real high-temperature conditions.

[0008] The objective of this invention can be achieved through the following technical solutions:

[0009] A wafer-level packaged chip X-ray imaging in-situ heating characterization device includes:

[0010] A rotating platform and a sample chamber placed on the rotating platform, with the wafer to be tested placed inside the sample chamber;

[0011] The sample chamber cover includes a cover body, an infrared heating plate, and a non-contact temperature probe. The infrared heating plate is located on the cover body and faces the sample chamber. The infrared heating plate and the wafer to be tested are arranged in parallel and their centers are aligned. The non-contact temperature probe is located on the cover body and is used to detect the temperature inside the sample chamber and the temperature of the infrared heating plate.

[0012] An infrared heating temperature controller is connected to an infrared heating plate and a non-contact temperature probe, respectively, and is configured to adjust the power of the infrared heating plate according to the temperature value collected by the non-contact temperature probe.

[0013] A 4D X-ray CT scanner is used to scan wafers for inspection.

[0014] The chamber cover also includes a bearing. The inner ring of the bearing is fitted around the outside of the infrared heating plate and is stationary relative to the infrared heating plate. The outer wall of the outer ring of the bearing contacts the inner wall of the side of the sample chamber and rotates with the rotation of the sample chamber.

[0015] The non-contact temperature probe is located on the back of the chamber cover body, and the chamber cover body is provided with a temperature measuring hole. The non-contact temperature probe is positioned aligned with the temperature measuring hole, wherein the back of the chamber cover body faces away from the sample chamber.

[0016] The temperature measuring hole is located near the outer edge of the main body of the bin cover.

[0017] The infrared heating plate also includes a heating plate body and an infrared heating wire disposed within the heating plate body, wherein the infrared heating wire is arranged in a spiral shape.

[0018] The non-contact temperature probe is located on the back of the chamber cover body, and the chamber cover body is provided with a temperature measuring hole. The non-contact temperature probe is aligned with the temperature measuring hole. The back of the chamber cover body is the side facing away from the sample chamber. The projection of the temperature measuring hole on the plane of the infrared heating plate is located outside the area of ​​the infrared heating plate.

[0019] The infrared heating temperature controller is connected to the infrared heating plate via a heating bracket, which passes through the center of the main body of the compartment cover.

[0020] The rotating platform includes a rotating table, a lifting rod, and a base. The base is connected to the rotating table via the lifting rod and rotates with the rotating table. The sample chamber is disposed on the base and fixed to the base by static friction.

[0021] The length of the lifting rod is limited by a limiting pin.

[0022] The non-contact temperature probe is an infrared temperature measurement probe.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] 1. By designing an infrared heating plate for heating, on the one hand, the problem of excessively high thermal gradient within the wafer plane can be solved, which can meet the stringent requirements of advanced packaging processes for heating temperature uniformity. On the other hand, it will not generate strong X-ray scattering noise that obscures the structural evolution of micron-level solder joints or vias inside the chip, and the internal failure dynamics of the packaged chip under real high-temperature conditions can be directly observed.

[0025] 2. By setting the outer ring of the bearing to contact the inner wall of the sample chamber side and rotating with the sample chamber, the base and sample chamber can rotate smoothly during the test. This ensures stable heating of the packaged chip and avoids abnormal data acquisition and subsequent reconstruction imaging caused by sample instability during the detection process.

[0026] 3. It can directly capture the failure dynamics of packaged chips at high temperatures, such as solder joint fracture, interface delamination, and metal electromigration, breaking through the limitation of traditional destructive slicing which can only obtain static cross-sections.

[0027] 4. It allows direct observation of the thermal failure initiation point, guiding the optimization of packaging materials and structural design.

[0028] 5. It allows for non-destructive testing, enabling multiple cyclic tests on the same chip, significantly reducing sample consumption and experimental repetition costs.

[0029] 6. It can simultaneously record temperature, current / voltage signals and CT images to establish a complete causal chain of "temperature gradient → resistance change → structural failure". Attached Figure Description

[0030] Figure 1 This is a schematic diagram of the structure of the present invention;

[0031] Figure 2 This is a schematic diagram of the heating element;

[0032] Figure 3 This is a top view of the heating section;

[0033] The components are as follows: 1-01, Rotary stage; 1-02, Lifting rod; 1-03, Base; 1-04, Sample chamber; 1-05, Chamber cover; 1-06, Non-contact temperature probe; 1-07, Infrared heating temperature controller; 2-01, Sample stage; 2-02, Chamber cover body; 2-04, Bearing; 2-05, Infrared heating plate; 3-03, Infrared heating wire; 3-04, Temperature measuring hole. Detailed Implementation

[0034] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. These embodiments are based on the technical solution of the present invention and provide detailed implementation methods and specific operating procedures. However, the scope of protection of the present invention is not limited to the following embodiments.

[0035] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0036] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "proximal," "distal," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance. Physical quantities in formulas, unless otherwise specified, should be understood as basic quantities in the International System of Units (SI), or derived quantities derived from basic quantities through mathematical operations such as multiplication, division, differentiation, or integration.

[0037] Furthermore, terms such as "horizontal," "vertical," and "sag" do not imply that components must be absolutely horizontal or suspended, but rather that they can be slightly tilted. For example, "horizontal" simply means that its direction is more horizontal relative to "vertical," and does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0038] In the description of this invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0039] A wafer-level packaged chip X-ray imaging in-situ heating characterization device, such as Figure 1 As shown, it includes:

[0040] A rotating platform and a sample chamber 1-04 placed on the rotating platform; the wafer to be tested is placed in the sample chamber 1-04.

[0041] The chamber cover 1-05 includes a chamber cover body 2-02, an infrared heating plate 2-05, and a non-contact temperature probe 1-06. The infrared heating plate 2-05 is located on the chamber cover body 2-02 and faces the sample chamber 1-04. The infrared heating plate 2-05 and the wafer to be tested are arranged parallel to each other and their centers are aligned. The non-contact temperature probe 1-06 is located on the chamber cover body 2-02 and is used to detect the temperature of the infrared heating plate 2-05 inside the sample chamber 1-04.

[0042] Infrared heating temperature controller 1-07 is connected to infrared heating plate 2-05 and non-contact temperature probe 1-06 respectively, and is configured to adjust the power of infrared heating plate 2-05 according to the temperature value collected by non-contact temperature probe 1-06.

[0043] A 4D X-ray CT scanner is used to scan wafers for inspection.

[0044] By designing an infrared heating plate 2-05 for heating, on the one hand, the problem of excessively high thermal gradient within the wafer plane can be solved, which can meet the stringent requirements of advanced packaging processes for heating temperature uniformity. On the other hand, it will not generate strong X-ray scattering noise that obscures the structural evolution of micron-level solder joints or vias inside the chip, and the internal failure dynamics of the packaged chip under real high-temperature conditions can be directly observed.

[0045] In this embodiment, the cover 1-05 also includes a bearing 2-04. The inner ring of the bearing 2-04 is fitted around the outside of the infrared heating plate 2-05 and is stationary relative to the infrared heating plate 2-05. The outer wall of the outer ring of the bearing 2-04 contacts the inner wall of the side of the sample compartment 1-04 and rotates with the rotation of the sample compartment 1-04. Thus, by adding the bearing 2-04, the cover 1-05 and the sample compartment 1-04 can be in contact with each other, thereby achieving a certain degree of spatial enclosure between them, but not a complete seal. This ensures that the sample rotates smoothly with the base, is heated evenly, and that imaging information data is acquired stably, achieving stable, high-resolution imaging of the packaged chip. Of course, in other embodiments, the bearing 2-04 may be omitted, and the cover 1-05 and the sample compartment 1-04 may not be in contact with each other.

[0046] In this embodiment, the non-contact temperature probe 1-06 is disposed on the back of the chamber cover body 2-02. The chamber cover body 2-02 has a temperature measuring hole, and the non-contact temperature probe 1-06 is aligned with the temperature measuring hole. The back of the chamber cover body 2-02 faces away from the sample chamber 1-04. This structure, which fixes the non-contact temperature probe to the back of the chamber cover, can maintain a stable alignment between the probe and the temperature measuring hole to a maximum extent, thereby ensuring accurate and stable readings. Of course, in other embodiments, it can also be disposed on the front of the chamber cover body 2-02, i.e., the side facing the sample chamber 1-04, or on the side of the chamber cover body 2-02. However, this side-mounted design requires a certain gap between the chamber cover 1-05 and the sample chamber 1-04, which can lead to a large temperature difference between the inside and outside of the chamber, causing heat conduction and affecting the stability of the probe readings.

[0047] In this embodiment, the temperature measuring hole is located near the outer edge of the main body 2-02 of the compartment cover. Thus, once the temperature probe reading stabilizes, it indicates that the temperature of the non-concentrated heating area has also reached the set temperature, thereby determining that the temperature inside the compartment has been kept consistent, achieving uniform heating of the packaged chip.

[0048] In this embodiment, the infrared heating plate 2-05 also includes a heating plate body and an infrared heating wire 3-03 disposed in the heating plate body. The infrared heating wire 3-03 is spirally arranged, and the projection of the temperature measuring hole on the plane of the infrared heating plate 2-05 is located outside the area of ​​the infrared heating plate 2-05.

[0049] The infrared heating temperature controller 1-07 is connected to the infrared heating plate 2-05 through a heating bracket, which is set through the center of the main body of the cover 2-02.

[0050] In this embodiment, the rotating platform includes a rotating stage 1-01, a lifting rod 1-02, and a base 1-03. The base 1-03 is connected to the rotating stage 1-01 via the lifting rod 1-02 and rotates with the rotating stage 1-01. The sample chamber 1-04 is mounted on the base 1-03 and fixed to the base by static friction. The rotation of the rotating stage 1-01 drives the lifting rod 1-02 and the base 1-03, along with the sample chamber 1-04, to rotate together. During rotation, the wafer can be heated sufficiently and uniformly, avoiding unevenness in the longitudinal dimension. The rotating stage 1-01 is driven by a high-precision stepper motor, enabling 360-degree rotation with a rotation accuracy of 0.1 degrees, ensuring stable sample rotation during X-ray CT scanning. The lifting rod is made of aluminum alloy, featuring lightweight and high strength characteristics. Its diameter is 20mm, and its length is adjustable from 100mm to 200mm to accommodate different detection heights. The base is made of stainless steel with a precision-machined surface to ensure sufficient static friction between it and the sample chamber, preventing relative sliding of the sample chamber during rotation.

[0051] In this embodiment, the lifting rod 1-02 is length-limited by a limiting pin, thus enabling different length limits. Generally, in most embodiments, the non-contact temperature probe 1-06 is an infrared temperature probe, installed on the back of the main body of the compartment cover, aligned with the temperature measuring hole. The infrared temperature probe has a temperature measuring range of -50℃ to 500℃, a measuring accuracy of ±1℃, and a response time of less than 100ms. The infrared temperature probe is connected to the infrared heating temperature controller via a signal line to transmit temperature data in real time.

[0052] The usage process of this application is as follows:

[0053] S1: Prepare the sample. Place the packaged wafer in the sample chamber 1-04, adjust the position so that the sample is in the heating area, adjust the height of the lifting rod, and turn on the rotary table 101.

[0054] S2: Turn on the infrared heating temperature controller 1-07, set the test temperature, and wait for the temperature reading of the non-contact temperature probe 1-06 to stabilize.

[0055] S3: Use 4D X-ray CT technology to scan the wafer under test and acquire data information.

[0056] S4: Use the VoxeStudio Recon tool to preprocess the tomographic scan information.

[0057] S5: Use Dragonfly software to visualize and 3D reconstruct the pre-reconstructed information, and observe the high-temperature operating conditions of the packaged chip in situ.

[0058] The sample chamber has a cylindrical structure and is made of polytetrafluoroethylene (PTFE), which has good high-temperature resistance and X-ray permeability. The interior of the sample chamber has recesses for placing the wafer; the recess depth is 2mm, and the diameter is designed according to the size of the wafer to be tested, typically 8 inches (approximately 200mm) or 12 inches (approximately 300mm). The bottom of the sample chamber, in contact with the base, is precision ground, with a surface roughness Ra value not exceeding 0.8μm, ensuring sufficient contact area and static friction with the base.

[0059] The main body of the sample chamber cover is made of polytetrafluoroethylene (PTFE), and its diameter matches that of the sample chamber. A circular groove is cut into the center of the cover body for mounting an infrared heating plate. On the back of the cover body, the side facing away from the sample chamber, a temperature measuring hole is located near the outer edge. This hole penetrates the cover body, allowing a non-contact temperature probe to directly measure the temperature inside the sample chamber.

[0060] The infrared heating plate is installed in the central groove of the main body of the compartment cover. The infrared heating plate includes a main body and infrared heating wires arranged in a spiral pattern within the main body. The main body is made of aluminum nitride ceramic material, which has excellent thermal conductivity and electrical insulation. The infrared heating wires are made of nickel-chromium alloy, with a diameter of 0.5 mm and a total length of approximately 2000 mm. They are evenly distributed in a spiral pattern within the main body, with a spiral spacing of 5 mm. The maximum operating temperature of the infrared heating plate can reach 400℃, with a power of 500W and an operating voltage of 220V.

[0061] The infrared heating temperature controller is connected to the infrared heating plate via a heating bracket made of stainless steel, which passes through the center of the chamber cover. The infrared heating temperature controller employs a PID control algorithm with a control accuracy of ±0.5℃. It automatically adjusts the output power of the infrared heating plate based on the difference between the set temperature and the actual measured temperature, achieving precise temperature control. The infrared heating temperature controller has an overheat protection function; when the temperature exceeds the set upper limit, it automatically cuts off the heating power to prevent sample overheating and damage.

[0062] The 4D X-ray CT scanner includes an X-ray source, an X-ray detector, and a data acquisition system. The X-ray source operates at a voltage range of 40kV to 160kV and a current range of 50μA to 500μA, with a focal spot size of less than 5μm, ensuring high-resolution imaging. The X-ray detector is a flat-panel detector with an effective detection area of ​​400mm × 400mm, a pixel size of 100μm × 100μm, and a grayscale resolution of 16 bits. The data acquisition system includes a high-speed data acquisition card and an image reconstruction workstation, enabling real-time data acquisition and 3D reconstruction.

[0063] During use, the wafer to be tested is first placed in the groove within the sample chamber, and then the chamber lid is placed on top, ensuring the infrared heating plate is parallel to and centered on the wafer. The desired heating temperature and rate are set via the infrared heating temperature controller, and the infrared heating plate begins heating. A non-contact temperature probe monitors the temperature inside the sample chamber in real time through a temperature sensor. Based on the actual temperature data fed back by the temperature probe, the infrared heating temperature controller automatically adjusts the output power of the infrared heating plate to stabilize the temperature inside the sample chamber at the set value.

[0064] Once the temperature inside the sample chamber reaches the set value and stabilizes, the 4D X-ray CT scanner is activated for scanning. The rotating stage rotates the base, sample chamber, and wafer within it. X-rays emitted from the X-ray source pass through the wafer and are received by the X-ray detector, forming a projected image. By acquiring multi-angle projected images through 360-degree rotation, the data acquisition system performs three-dimensional reconstruction on these images to obtain a three-dimensional model of the wafer's internal structure. Throughout the scanning process, the infrared heating temperature controller continuously operates to maintain a constant temperature inside the sample chamber, enabling in-situ X-ray imaging inspection of the wafer under high-temperature conditions.

Claims

1. A wafer-level packaged chip X-ray imaging in-situ heating characterization device, characterized in that, include: A rotating platform and a sample chamber (1-04) placed on the rotating platform, with the wafer to be tested placed in the sample chamber (1-04); The chamber cover (1-05) includes a chamber cover body (2-02), an infrared heating plate (2-05), and a non-contact temperature probe (1-06). The infrared heating plate (2-05) is located on the chamber cover body (2-02) and faces the sample chamber (1-04). The infrared heating plate (2-05) and the wafer to be tested are arranged parallel to each other and their centers are aligned. The non-contact temperature probe (1-06) is located on the chamber cover body (2-02) and is used to detect the temperature of the infrared heating plate (2-05) inside the sample chamber (1-04). An infrared heating temperature controller (1-07) is connected to an infrared heating plate (2-05) and a non-contact temperature probe (1-06) respectively, and is configured to adjust the power of the infrared heating plate (2-05) according to the temperature value collected by the non-contact temperature probe (1-06); A 4D X-ray CT scanner is used to scan wafers for inspection.

2. The wafer-level packaged chip X-ray imaging in-situ heating characterization device according to claim 1, characterized in that, The chamber cover (1-05) also includes a bearing (2-04). The inner ring of the bearing (2-04) is fitted on the outside of the infrared heating plate (2-05) and is stationary relative to the infrared heating plate (2-05). The outer wall of the outer ring of the bearing (2-04) contacts the inner wall of the side of the sample chamber (1-04) and rotates with the rotation of the sample chamber (1-04).

3. The wafer-level packaged chip X-ray imaging in-situ heating characterization device according to claim 1, characterized in that, The non-contact temperature probe (1-06) is located on the back of the chamber cover body (2-02). The chamber cover body (2-02) is provided with a temperature measuring hole. The non-contact temperature probe (1-06) is aligned with the temperature measuring hole. The back of the chamber cover body (2-02) is the side facing away from the sample chamber (1-04).

4. The wafer-level packaged chip X-ray imaging in-situ heating characterization device according to claim 3, characterized in that, The temperature measuring hole is located near the outer edge of the main body of the cover (2-02).

5. The wafer-level packaged chip X-ray imaging in-situ heating characterization device according to claim 1, characterized in that, The infrared heating plate (2-05) also includes a heating plate body and an infrared heating wire (3-03) disposed in the heating plate body, wherein the infrared heating wire (3-03) is arranged in a spiral shape.

6. The wafer-level packaged chip X-ray imaging in-situ heating characterization device according to claim 5, characterized in that, The non-contact temperature probe (1-06) is located on the back of the chamber cover body (2-02). The chamber cover body (2-02) is provided with a temperature measuring hole. The non-contact temperature probe (1-06) is aligned with the temperature measuring hole. The back of the chamber cover body (2-02) faces away from the sample chamber (1-04). The projection of the temperature measuring hole on the plane of the infrared heating plate (2-05) is located outside the area of ​​the infrared heating plate (2-05).

7. The wafer-level packaged chip X-ray imaging in-situ heating characterization device according to claim 1, characterized in that, The infrared heating temperature controller (1-07) and the infrared heating plate (2-05) are connected by a heating bracket, which is set through the center of the main body of the cover (2-02).

8. The wafer-level packaged chip X-ray imaging in-situ heating characterization device according to claim 1, characterized in that, The rotating platform includes a rotating table (1-01), a lifting rod (1-02), and a base (1-03). The base (1-03) is connected to the rotating table (1-01) via the lifting rod (1-02) and rotates with the rotating table (1-01). The sample chamber (1-04) is disposed on the base (1-03) and fixed to the base by static friction.

9. The wafer-level packaged chip X-ray imaging in-situ heating characterization device according to claim 8, characterized in that, The lifting rod (1-02) is length-limited by a limiting pin.

10. The wafer-level packaged chip X-ray imaging in-situ heating characterization device according to claim 1, characterized in that, The non-contact temperature probe (1-06) is an infrared temperature measurement probe.

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