Temperature sensor, packaging structure and temperature monitoring method

Abstract

The invention discloses a temperature sensor, a packaging structure and a temperature monitoring method. The temperature sensor comprises: a first PDMS structure; a second PDMS structure; the shell wraps the first PDMS structure and the second PDMS structure, and an air cavity is formed between the first PDMS structure and the second PDMS structure; and the temperature monitoring structure is used for monitoring the volume change of the air cavity caused by the deformation of the first PDMS structure and the second PDMS structure, and calculating the temperature of the point to be measured according to the volume change of the air cavity. By adopting the scheme, real-time temperature monitoring can be realized.

Description

Technical Field

[0001] This invention relates to the field of semiconductor technology, and specifically to a temperature sensor, packaging structure, and temperature monitoring method. Background Technology

[0002] With the continuous development of major trends such as 5G, consumer electronics, storage and computing, Internet of Things, and artificial intelligence, the application market demands increasingly higher chip performance, lower power consumption per unit area, and higher density, thus leading to the development of advanced packaging.

[0003] While advanced packaging technologies improve performance, their high integration levels can lead to overheating, impacting device reliability. Therefore, monitoring the temperature of the package becomes a critical issue that needs to be addressed.

[0004] However, existing temperature monitoring methods are not yet fully developed, and often rely on reliability testing to determine the impact of heat emitted by the package on the package. However, it is difficult to monitor the temperature of the package in real time using reliability testing methods. Summary of the Invention

[0005] The problem this invention aims to solve is: how to achieve real-time temperature monitoring.

[0006] To address the above problems, embodiments of the present invention provide a temperature sensor, the temperature sensor comprising:

[0007] First PDMS structure;

[0008] Second PDMS structure;

[0009] The housing encloses the first PDMS structure and the second PDMS structure, and forms an air cavity between the first PDMS structure and the second PDMS structure;

[0010] A temperature monitoring structure is used to monitor the volume change of the air cavity caused by the deformation of the first PDMS structure and the second PDMS structure, and to calculate the temperature of the point to be measured based on the volume change of the air cavity.

[0011] In one possible embodiment, the shell is made of epoxy resin or quartz.

[0012] In one possible embodiment, the temperature monitoring structure is located outside the housing.

[0013] In one possible embodiment, the temperature monitoring structure includes:

[0014] A receiving unit, connected to the air cavity, is used to receive the air squeezed out of the air cavity;

[0015] A calculation unit, connected to the receiving unit, is used to calculate the temperature of the point to be measured based on the air volume received by the receiving unit.

[0016] In one possible embodiment, the computing unit is used to convert the air volume received by the receiving unit using the thermal expansion coefficients of the first PDMS structure and the second PDMS structure to obtain the temperature at the location corresponding to the temperature sensor.

[0017] In one possible embodiment, the shape of the housing matches the surface shape of the point to be measured.

[0018] In one possible embodiment, the first PDMS structure, the air cavity, and the second PDMS structure are arranged along a first direction within the housing.

[0019] This invention also provides a packaging structure, the packaging structure comprising:

[0020] Encapsulation cavity;

[0021] The packaging substrate is located within the packaging cavity;

[0022] The chip is located within the packaging cavity and above the packaging substrate.

[0023] And any of the above-mentioned temperature sensors, wherein the housing is in contact with the chip, and the temperature sensor is used to monitor the temperature of the point to be measured on the chip.

[0024] In one possible embodiment, the temperature monitoring structure is located inside the packaging cavity and outside the housing.

[0025] In one possible embodiment, the temperature monitoring structure is located outside the packaging cavity.

[0026] In one possible embodiment, the material of the housing has the same coefficient of thermal expansion as the encapsulation cavity.

[0027] In one possible embodiment, both the material of the housing and the material of the encapsulation cavity are epoxy resin.

[0028] In one possible embodiment, two or more temperature sensors are disposed on the same chip.

[0029] In one possible embodiment, the distance between adjacent temperature sensors on the same chip is 2mm to 5mm.

[0030] This invention also provides a temperature monitoring method, the method comprising:

[0031] A packaging cavity is provided, wherein a packaging template is disposed within the packaging cavity, and a chip is located on the packaging template;

[0032] A temperature sensor according to any one of claims 1 to 7 is disposed within the filling space of the packaging cavity and at the test point of the chip;

[0033] The temperature sensor is used to monitor the temperature at the point to be measured on the chip.

[0034] Compared with the prior art, the technical solution of the embodiments of the present invention has the following advantages:

[0035] By employing the scheme of this invention, a first PDMS structure and a second PDMS structure are set up, and an air cavity is formed between the first PDMS structure and the second PDMS structure. The volume of this air cavity changes due to the deformation of the first PDMS structure and the second PDMS structure. Therefore, a temperature monitoring structure can be used to monitor the volume change of the air cavity, and the temperature of the measured point can be calculated based on the volume change of the air cavity, thus achieving real-time temperature monitoring. Subsequently, this temperature sensor can be applied to the chip surface within the package structure, thereby enabling real-time monitoring of the package temperature. Attached Figure Description

[0036] Figure 1 This is a schematic diagram of the structure of a temperature sensor according to an embodiment of the present invention;

[0037] Figure 2 This is a schematic diagram of a packaging structure according to an embodiment of the present invention;

[0038] Figure 3 This is a schematic diagram of another packaging structure in an embodiment of the present invention;

[0039] Figure 4 This is a flowchart of a temperature monitoring method according to an embodiment of the present invention. Detailed Implementation

[0040] Currently, reliability testing is often required to determine the impact of heat dissipated by the package on the package. However, it is difficult to monitor the temperature of the package in real time using reliability testing methods, so it is impossible to take corresponding measures before the heat dissipated by the package affects the reliability of the package.

[0041] To address this problem, the present invention provides a temperature sensor that can be placed at the point to be measured and can monitor the temperature of the point in real time, thereby enabling real-time temperature monitoring.

[0042] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0043] Reference Figure 1 This invention provides a temperature sensor 10, which may include: a first PDMS structure 11, a second PDMS structure 12, a housing 13, and a temperature monitoring structure 14. Wherein:

[0044] The housing 13 encloses the first PDMS structure 11 and the second PDMS structure 12, and forms an air cavity 15 between the first PDMS structure 11 and the second PDMS structure 12.

[0045] The temperature monitoring structure 14 is used to monitor the volume change of the air cavity 15 caused by the deformation of the first PDMS structure 11 and the second PDMS structure 12, and to calculate the temperature of the point to be measured based on the volume change of the air cavity 15.

[0046] Polydimethylsiloxane (PDMS) is a thermosensitive material, a mixture of an elastic polymer (Sylgard 184-A) and a hardener (Sylgard 184-B) in a specific ratio. PDMS is liquid at low temperatures and solidifies as the temperature gradually increases. PDMS exhibits excellent thermal expansion properties, expanding under temperature changes, and also possesses good adhesion, heat resistance, cold resistance, water resistance, and chemical inertness. Typically, the ratio of elastic polymer (Sylgard 184-A) to hardener (Sylgard 184-B) in PDMS is 10:1. Experiments have shown that under certain conditions, within the temperature range of 40–42°C, PDMS sensors can achieve a temperature sensitivity of approximately -20.55 nm / °C.

[0047] In a specific implementation, heating the PDMS material at 80°C for 1 hour yields a solid first PDMS structure 11 and a solid second PDMS structure 12, which remain solid at room temperature. The first PDMS structure 11 and the second PDMS structure 12 are then enclosed in a housing 13, forming an air cavity 15 between them.

[0048] In specific implementations, the housing 13 can be made of epoxy resin, quartz, or other materials that are not sensitive to heat. As the outer shell of the temperature sensor, the housing 13 keeps the first PDMS structure 11 and the second PDMS structure 12 in a fixed position, thus securing them at the measurement point. When the temperature at the measurement point rises, the first PDMS structure 11 and the second PDMS structure 12 deform, increasing their volume and compressing the air cavity 15. Excess air in the air cavity 15 is then forced into the temperature monitoring structure 14, which calculates the temperature of the measurement point based on the change in volume within the air cavity 15.

[0049] In specific implementations, the temperature monitoring structure 14 can be located outside the housing 13, and its positional relationship with the housing is not limited. For example, it can be set on the surface of the housing 13 or it can be located away from the housing 13.

[0050] In one embodiment, the temperature monitoring structure 14 may include a receiving unit and a computing unit. The receiving unit is connected to the air cavity 15 and is used to receive air expelled from the air cavity 15. The computing unit is connected to the receiving unit and is used to calculate the temperature of the temperature sensor's measurement point based on the volume of air received by the receiving unit.

[0051] In a specific implementation, the volume of the air cavity 15 changes under the compression of the first PDMS structure 11 and the second PDMS structure 12. The calculation unit can use the thermal expansion coefficients of the first PDMS structure and the second PDMS structure to convert the air volume received by the receiving unit to obtain the temperature at the corresponding location of the temperature sensor.

[0052] Assuming the volumetric thermal expansion coefficient of PDMS is 9.6 × 10⁻⁴ / ℃, the volume of the solid first PDMS structure 11 and the second PDMS structure 12 increases or decreases by approximately 9.6% with a temperature difference of 100℃. At room temperature and pressure, the average thermal expansion coefficient of the air cavity 15 is approximately 3.67 × 10⁻⁴ / ℃. -3 / ℃, the total volume of the first PDMS structure 11 and the second PDMS structure 12 is V1, and the volume of the air cavity is V2.

[0053] The initial volume received by the receiving unit is 0. The volume of air squeezed into the receiving unit by the air cavity is δV. Then the displayed temperature T = ambient temperature + δT, where:

[0054] δV1= 9.6× 10 -4 / ℃ *V1*δT; (1)

[0055] δV2= 3.67×10-3 / ℃ *V2*δT; (2)

[0056] δV=δV1+δV2=(9.6×10 -4 / ℃*V1+ 3.67×10 -3 / ℃*V2)* δT; (3)

[0057] δT=δV / (9.6× 10 -4 / ℃ *V1+ 3.67×10 -3 / ℃ *V2); (4)

[0058] If V1, V2, and δV are all known values, then the specific value of the displayed temperature T can be measured.

[0059] In a specific implementation, the temperature monitoring structure 14 may also include a display unit, which can display the temperature value calculated by the calculation unit.

[0060] In some embodiments, the temperature monitoring structure 14 may further include an alarm unit, which may also compare the temperature value obtained by the calculation unit with a preset temperature threshold, and output an alarm signal, such as a voice alarm signal, when the temperature value obtained by the calculation unit is greater than the preset temperature threshold.

[0061] In specific implementations, the shape of the housing 13 matches the shape of the surface of the point to be measured, meaning that the surface of the housing fits snugly against the surface of the point to be measured, thereby achieving accurate temperature monitoring. For example, when the surface of the point to be measured is planar, one surface of the housing 13 can be set to be planar. In this case, the first PDMS structure 11 and the second PDMS structure 12 inside the housing 13 can be rectangular or rectangular, for example, both can be cubes with equal side lengths.

[0062] For example, when the surface of the point to be measured is concave, one surface of the housing can be set as a convex surface that matches the concave surface, so that the housing can fit well against the surface of the point to be measured. In this case, the first PDMS structure 11 and the second PDMS structure 12 inside the housing 13 can be circular.

[0063] In a specific implementation, the air cavity 15 is located between the first PDMS structure 11 and the second PDMS structure 12. The first PDMS structure 11 and the second PDMS structure 12 can be symmetrically distributed with respect to the center of the housing 13, thereby allowing the first PDMS structure 11, the air cavity 15 and the second PDMS structure 12 to be arranged along a first direction within the housing 13, which can be any direction.

[0064] Using the aforementioned temperature sensor, and leveraging the thermal properties of PDMS, a sandwich structure is formed consisting of a first PDMS structure 11, an air cavity 15, and a second PDMS structure 12 to achieve real-time temperature monitoring. The temperature sensor can be applied within a package to monitor the surface temperature of the chip within the package, or it can be applied to other semiconductor structures; no limitation is made here.

[0065] This invention also provides a packaging structure, see reference. Figure 1 The packaging structure may include:

[0066] Encapsulation cavity 21;

[0067] The packaging substrate 22 is located within the packaging cavity 21;

[0068] Chip 23 is located inside the packaging cavity 21 and above the packaging substrate 22;

[0069] And any of the above-mentioned temperature sensors, wherein the housing is in contact with the chip 23, and the temperature sensor is used to monitor the temperature of the point to be measured on the chip 23.

[0070] In practical implementation, a single temperature sensor, or two or more temperature sensors, can be set on the same chip. By setting multiple temperature sensors on the chip surface, not only can the temperature values ​​of each measured point on the chip be obtained based on each temperature sensor, but the temperature values ​​measured at each measuring point can also be quantitatively compared, and the temperature gradient between these measuring points can be calculated to analyze and statistically analyze the chip's heat dissipation.

[0071] In practical implementation, when multiple temperature sensors are placed on the chip surface, the temperature sensors can be located on the top surface and sidewalls of the chip. The specific locations can be adjusted according to the locations of the test points defined on the chip. These test points can be locations on the chip where heat dissipation problems frequently occur, determined based on practical experience. For example, refer to... Figure 2 The chip 23 can be configured with five test points, and each test point can be configured with a temperature sensor, resulting in a total of five temperature sensors: a first temperature sensor 241, a second temperature sensor 242, a third temperature sensor 243, a fourth temperature sensor 244, and a fourth temperature sensor 245. The first temperature sensor 241 to the third temperature sensor 243 are located on the top surface of the chip 23. The fourth temperature sensor 244 and the fourth temperature sensor 245 are located on the sidewalls of the chip 23.

[0072] In practical implementation, the distance between adjacent temperature sensors on the chip surface can be 2mm to 5mm. Multiple temperature sensors can be divided into multiple groups, with each group monitoring the heat dissipation of a specific area on the chip surface. Each group of temperature sensors can be arranged on the same chip surface at different angles as needed.

[0073] In practice, the housing of each temperature sensor is tightly fitted to the chip surface, thereby avoiding temperature transfer loss.

[0074] In practice, each temperature sensor has its own temperature monitoring structure. In one embodiment, the temperature monitoring structure can be located inside the packaging cavity 21 and outside the housing of the temperature sensor, thereby facilitating the transportation of the packaging structure.

[0075] In other embodiments, the temperature monitoring structure may also be located outside the packaging cavity. For example, the temperature monitoring structure may be placed on the outer surface of the packaging cavity to facilitate the display of monitoring results.

[0076] In practical implementation, the material of the encapsulation cavity 21 is mostly epoxy resin (EPC), which has balanced physical properties and many advantages, such as high adhesion, low shrinkage, and high electrical insulation. During encapsulation, the encapsulation substrate 22 and the chip 23 are first fixed in the encapsulation cavity 21, and the encapsulation substrate 22 can provide support for the chip 23. Then, a temperature sensor is fixed on the surface of the chip 23 inside the encapsulation cavity 21. Specifically, the temperature sensor can be fixed to the surface of the chip 23 by means of polymer adhesive, which can be epoxy resin.

[0077] In practical implementation, two or more chips can be placed inside the same package structure. These two or more chips are located on the same package substrate, and each chip can be equipped with at least one temperature sensor. For example, refer to... Figure 3 A first chip 32 and a second chip 33 are disposed on the packaging substrate 31. A first temperature sensor 341, a second temperature sensor 342, and a third temperature sensor 343 are disposed on the first chip 32, and a fourth temperature sensor 344, a fifth temperature sensor 345, and a sixth temperature sensor 346 are disposed on the second chip 33. The packaging substrate 31, the first chip 32, the second chip 33, and all temperature sensors are located in the same packaging cavity 36.

[0078] In practical implementation, when the heat generated by the chip is conducted to the temperature sensor, there will be a certain temperature loss, which is the temperature coefficient. After obtaining the measured value from the temperature sensor, the quotient of this measured value and the temperature coefficient can be used as the actual temperature value of the chip's measured point. This temperature coefficient is determined by the material and thickness of the packaging cavity and the temperature sensor's outer shell. Once the material and thickness of the packaging cavity and the temperature sensor's outer shell are determined, this temperature coefficient will not change.

[0079] In practical implementation, when the heat generated by the chip is conducted to the temperature sensor, there will be a certain temperature loss. This temperature coefficient is determined by the materials and thicknesses of the packaging cavity and the temperature sensor housing. A higher temperature coefficient indicates better heat transfer. The temperature coefficient is not a constant value; it depends on the specific properties of the material, such as its heat capacity, density, and thermal conductivity, as well as the surface geometry and roughness. Once the materials and thicknesses of the packaging cavity and the temperature sensor housing are determined, this temperature coefficient will not change. To facilitate the calculation of the actual temperature value at the chip's measurement point, the material of the housing can be set to have the same coefficient of thermal expansion as the packaging cavity. Simultaneously, before using the temperature sensor, the actual temperature of the materials should be measured to determine the temperature loss under the combined thickness of the packaging cavity and the temperature sensor housing. The temperature sensor housing thickness should be as thin as possible, ideally less than 1 mm.

[0080] In another embodiment, the materials of the shell and the encapsulation cavity may have different coefficients of thermal expansion. In this case, to avoid deviations in temperature measurement, when the encapsulation cavity material is different or the encapsulation form changes, the temperature coefficient needs to be re-measured through actual measurements. The same encapsulated product (same encapsulation cavity material and thickness, same shell material and thickness) only needs to be calculated once and can be used universally afterwards.

[0081] It should be noted that in practical applications, ambient temperature can also affect the temperature sensor. Therefore, the ambient temperature needs to be tested before the temperature sensor is implanted into the package. The ambient temperature can then be displayed through the temperature monitoring structure of the temperature sensor, which facilitates the analysis of the chip's heat dissipation capacity.

[0082] The packaging structure in this embodiment of the invention has a temperature sensor inside, which can monitor the chip temperature in real time, making it easier to understand the chip's heat dissipation and take appropriate measures.

[0083] Reference Figure 4 This invention also provides a temperature monitoring method, which may include:

[0084] Step 41: Provide a packaging cavity, wherein a packaging template and a chip are disposed within the packaging cavity.

[0085] For example, refer to Figure 3 The encapsulation cavity 36 is provided with an encapsulation substrate 31, and a first chip 32 and a second chip 33 located on the encapsulation substrate 32.

[0086] Step 42: Set a temperature sensor at the test point of the chip within the filling space of the packaging cavity.

[0087] For example, refer to Figure 3 The encapsulation cavity 36 has a filling space between it and the first chip 32 and the second chip 33. A first temperature sensor 341 to a sixth temperature sensor 346 are disposed within this filling space. The first temperature sensor 341 to the sixth temperature sensor 346 can be in close contact with the chip surface and are stably positioned within the filling space.

[0088] Step 43: Use the temperature sensor to monitor the temperature at the point to be measured on the chip.

[0089] In practice, temperature sensors within the package structure can monitor the temperature at various test points on the chip. These monitored temperature values ​​can then be used to analyze and statistically assess the chip's heat dissipation capacity. Furthermore, if excessive heat is detected, timely cooling measures can be implemented to prevent any impact on chip reliability.

[0090] The present invention utilizes PDMS thermistor material to form a temperature sensor, making the temperature change of the chip within the package structure visible. This allows for intuitive and convenient monitoring of the chip temperature, providing auxiliary analysis for subsequent solutions to the problem of high chip heat.

[0091] While the present invention has been disclosed above, it is not limited thereto. Any person skilled in the art can make various modifications and alterations without departing from the spirit and scope of the invention; therefore, the scope of protection of the present invention should be determined by the scope defined in the claims.

Claims

1. A temperature sensor, characterized in that, include: First PDMS structure; Second PDMS structure; The housing encloses the first PDMS structure and the second PDMS structure, and forms an air cavity between the first PDMS structure and the second PDMS structure; A temperature monitoring structure is used to monitor the volume change of the air cavity caused by the deformation of the first PDMS structure and the second PDMS structure, and to calculate the temperature of the point to be measured based on the volume change of the air cavity.

2. The temperature sensor as described in claim 1, characterized in that, The shell is made of epoxy resin or quartz.

3. The temperature sensor as described in claim 1, characterized in that, The temperature monitoring structure is located outside the housing.

4. The temperature sensor as described in claim 1, characterized in that, The temperature monitoring structure includes: A receiving unit, connected to the air cavity, is used to receive the air squeezed out of the air cavity; A calculation unit, connected to the receiving unit, is used to calculate the temperature of the point to be measured based on the air volume received by the receiving unit.

5. The temperature sensor as described in claim 4, characterized in that, The calculation unit is used to convert the air volume received by the receiving unit using the thermal expansion coefficients of the first PDMS structure and the second PDMS structure, so as to obtain the temperature at the corresponding location of the temperature sensor.

6. The temperature sensor as described in claim 1, characterized in that, The shape of the housing matches the surface shape of the point to be measured.

7. The temperature sensor as described in claim 1, characterized in that, The first PDMS structure, the air cavity, and the second PDMS structure are arranged along a first direction within the housing.

8. A packaging structure, characterized in that, include: Encapsulation cavity; The packaging substrate is located within the packaging cavity; The chip is located within the packaging cavity and above the packaging substrate. And the temperature sensor according to any one of claims 1 to 7, wherein the housing is in contact with the chip, and the temperature sensor is used to monitor the temperature of the point to be measured on the chip.

9. The packaging structure as described in claim 8, characterized in that, The temperature monitoring structure is located inside the packaging cavity and outside the housing.

10. The packaging structure as described in claim 8, characterized in that, The temperature monitoring structure is located outside the packaging cavity.

11. The packaging structure as described in claim 8, characterized in that, The material of the shell has the same coefficient of thermal expansion as the encapsulation cavity.

12. The packaging structure as described in claim 8, characterized in that, Both the shell and the encapsulation cavity are made of epoxy resin.

13. The packaging structure as described in claim 8, characterized in that, Two or more temperature sensors are disposed on the same chip.

14. The packaging structure as described in claim 13, characterized in that, The distance between adjacent temperature sensors on the same chip is 2mm to 5mm.

15. A temperature monitoring method, characterized in that, include: A packaging cavity is provided, wherein a packaging template is disposed within the packaging cavity, and a chip is located on the packaging template; A temperature sensor according to any one of claims 1 to 7 is disposed within the filling space of the packaging cavity and at the test point of the chip; The temperature sensor is used to monitor the temperature at the point to be measured on the chip.

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