Package substrate with temperature detection function, power semiconductor module and manufacturing method thereof

Abstract

The application discloses a packaging substrate with temperature detection function, a power semiconductor module and a manufacturing method thereof, and belongs to the technical field of power semiconductor modules.The packaging substrate with temperature detection function comprises an integrally formed ceramic insulating layer having opposite first and second surfaces, a sensor mounting groove, an independent temperature sensor chip, an insulating filler and a three-dimensional interconnection structure configured to lead an electrical signal of the temperature sensor chip to an external pad on the second surface or side surface of the ceramic insulating layer.The packaging substrate can realize high-precision and fast-response measurement of the junction temperature of a power chip, eliminate temperature rise decoupling deviation, ensure excellent high-voltage electrical isolation reliability while realizing direct thermal coupling, and avoid medium breakdown risk.The manufacturing method is flexible, the reliability of the power semiconductor module is improved, the comprehensive cost is reduced, the long-term stability of temperature monitoring can be ensured while the fast and accurate electrical and thermal response characteristics of the sensing unit are ensured.

Description

Technical Field

[0001] This invention relates to the field of power semiconductor technology, and in particular to a packaging substrate with temperature detection function, a power semiconductor module, and a method for manufacturing the same. Background Technology

[0002] In the field of power semiconductors, traditional substrate architectures face the severe challenge of insufficient temperature monitoring accuracy. Current designs typically place temperature sensors on the surface of heat sinks or in peripheral circuit areas, resulting in significant spatial isolation from the power device mounting area. In current mainstream power module packaging architectures, temperature sensors are often integrated on the surface of heat dissipation structures or attached to the periphery of driver circuit boards to meet high-voltage electrical isolation requirements, failing to achieve direct contact with the heat source of the component. This leads to the measured temperature not reflecting the true junction temperature of the measured component. Furthermore, due to electrical isolation requirements, sensors are usually embedded within potting materials such as epoxy resin or silicone gel. The inherent low thermal conductivity of these materials forms a substantial thermal resistance barrier around the sensor, severely hindering effective heat transfer. This results in significant phase lag and amplitude attenuation in the monitoring signal, causing a significant time difference and steady-state deviation between the temperature data captured by the control system and the actual operating conditions. Moreover, with increasing usage time, the contact thermal resistance caused by aging of the colloid will irreversibly and continuously increase, severely limiting the long-term stability and reliability of temperature monitoring.

[0003] When power devices are in operation, the large current in the power circuit induces a significant Joule heating effect on the metal traces. This localized heating is coupled to nearby sensors through thermal conduction, decoupling the sensor temperature rise from the actual junction temperature of the chip and causing additional temperature rise deviation. The high-frequency electromagnetic field generated by the high-speed switching action of the power devices couples electromagnetic noise onto the sensor leads, further degrading the electrothermal response characteristics of the sensing unit. This results in the monitoring data failing to accurately reflect the thermal state of the power devices, constituting a technical bottleneck for high-precision temperature feedback. In addition, the electric field concentration effect inside the potting medium under transient high-voltage switching conditions can easily induce partial discharge and accelerate insulation performance degradation, potentially leading to dielectric breakdown and electrical short circuit risk between the sensor electrodes and the high-voltage unit. This poses a serious threat to the functional safety of the module, and current substrate processes cannot solve the temperature measurement deviation and reliability problems caused by traditional substrate architectures.

[0004] Chinese invention patent application number 201180053352.8 discloses a power semiconductor module and a method for manufacturing a power semiconductor module sintered together with a temperature sensor. The planar device is equipped with at least one flat bottom side specifically for sintering, and an electrical contact area exists on the surface opposite the sintering surface in the form of a metal contact surface. The surface on the upper side can be contacted by a common method from the group of wire bonding, brazing, sintering, or pressure contact. The device is a temperature sensor, on which a sinterable metallization portion is provided on a ceramic body on its bottom side, and an electrical contact surface for continuing electrical connection is provided on its ceramic body. However, in this method of manufacturing power semiconductor modules sintered together with a temperature sensor, the temperature sensor is not directly attached to the heat source of the component, which causes the test temperature to not reflect the true junction temperature of the component under test. If the temperature sensor is directly attached to the heat source of the component through this manufacturing method, it will lead to dielectric breakdown and cause an electrical short circuit risk between the sensor electrode and the high-voltage unit. In addition, the sensor temperature rise is decoupled from the actual junction temperature of the chip, which will cause additional temperature rise deviation. Furthermore, the electrothermal response characteristics of the sensing unit are affected, making it impossible to achieve high-precision temperature feedback for power semiconductor devices. Summary of the Invention

[0005] The purpose of this invention is to provide a packaging substrate with temperature detection function, a power semiconductor module, and a method for manufacturing the same.

[0006] To achieve the above objectives, the technical solution proposed by this invention is as follows:

[0007] A packaging substrate with temperature detection function includes:

[0008] An integrally formed ceramic insulating layer has a first surface and a second surface opposite to each other, the first surface being connected to the heat sink via a copper foil layer;

[0009] The sensor mounting groove is a recessed structure formed on the second surface;

[0010] An independent temperature sensor chip is housed within the sensor mounting slot;

[0011] An insulating filler is used to fill the gap between the temperature sensor chip and the inner wall of the sensor mounting groove. The material of the insulating filler is the same as the main material of the ceramic insulating layer.

[0012] And a three-dimensional interconnect structure configured to direct electrical signals from the temperature sensor chip to external pads on the second surface or side of the ceramic insulating layer.

[0013] The three-dimensional interconnect structure includes:

[0014] A conductor disposed at the bottom or side wall of the sensor mounting slot, the conductor being electrically connected to the electrodes of the temperature sensor chip;

[0015] The vertical conductive via extending from the surface of the ceramic insulating layer toward the conductor;

[0016] And an upper metal layer formed on the surface of the ceramic insulating layer, the upper metal layer being electrically connected to the conductor through the vertical conductive via and forming the outer pad.

[0017] The vertical conductive vias are metallized vias achieved through magnetron sputtering or molten metal self-filling processes.

[0018] The conductor is made of silver or copper paste formed by screen printing and sintering.

[0019] The ceramic insulating layer is made of alumina or silicon nitride.

[0020] When the ceramic insulating layer is made of alumina, the insulating filler is a sintered and cured alumina ceramic slurry;

[0021] When the ceramic insulating layer is made of silicon nitride, the insulating filler is a sintered and cured silicon nitride ceramic slurry.

[0022] Power semiconductor module, including:

[0023] Packaging substrate with temperature detection function;

[0024] The power semiconductor chip is directly fixed to the upper metal surface of the packaging substrate through a bonding layer, and at least partially overlaps with the sensor mounting groove in the vertical projection, so that the heat generated by the power semiconductor chip is directly conducted to the temperature sensor chip through the ceramic insulating layer.

[0025] A method for manufacturing a packaging substrate with temperature detection function, comprising the following steps:

[0026] a. A sensor mounting groove is formed on the second surface of the ceramic insulating layer;

[0027] b. A conductor is formed within the sensor mounting slot;

[0028] c. Install the independent temperature sensor chip into the sensor mounting slot and electrically connect its electrodes to the conductor;

[0029] d. Fill the gap between the temperature sensor chip and the mounting groove with a ceramic slurry of the same material as the ceramic insulation layer, and sinter and solidify it to form an insulating filler integrated with the ceramic insulation layer;

[0030] e. Forming a vertical conductive via extending from the outer surface of the ceramic insulating layer to the conductor;

[0031] f. An upper metal layer and external pads are disposed on the surface of the ceramic insulating layer, and electrically interconnected with the conductor through the vertical conductive via.

[0032] Step e includes: machining a vertically conductive via from a second surface of the ceramic insulating layer opposite to the first surface to expose the conductor; and subsequently forming a metal plating on the inner wall of the vertically conductive via by a magnetron sputtering process.

[0033] Step e includes: processing vertical conductive vias from the second surface of the ceramic insulating layer using a chemical etching process, using the conductor as an etching stop layer, and then metallizing the vertical conductive vias using a molten metal self-filling process.

[0034] The beneficial effects of this invention are:

[0035] The packaging substrate in this technical solution can achieve high-precision and fast-response measurement of the junction temperature of the power chip, eliminate temperature rise decoupling deviation, and ensure excellent high-voltage electrical isolation reliability while achieving direct thermal coupling, avoiding the risk of dielectric breakdown. Its manufacturing method is flexible, improves the reliability of the power semiconductor module, reduces the overall cost, and ensures the fast and accurate electrothermal response characteristics of the sensing unit while ensuring the long-term stability of temperature monitoring.

[0036] By embedding the temperature sensor inside the ceramic insulating layer through a manufacturing method compatible with existing processes, it can significantly shorten the heat transfer path to the sensor and reduce path loss during heat transfer, thereby significantly improving the heat transfer efficiency and enabling the sensor to accurately capture temperature changes at the top of the substrate.

[0037] When the temperature sensor is directly coupled to a ceramic substrate with high thermal conductivity, there is no need to use organic thermally conductive adhesive to achieve heat transfer, eliminating the thermal attenuation problem caused by the thermally conductive adhesive layer in traditional solutions, and ensuring that heat can be directly and efficiently transferred to the sensor.

[0038] This integrated architecture also avoids the defects of organic thermally conductive adhesive materials that are prone to thermal aging under long-term high-temperature environments, which leads to increased thermal resistance and deterioration of heat transfer performance, thus ensuring the long-term stability of temperature monitoring.

[0039] The ceramic insulation layer itself has excellent insulation properties, which can effectively isolate electromagnetic interference generated by other electrical components inside the module during operation, avoid interference signals from affecting the sensor temperature measurement signal, and greatly improve the accuracy of temperature measurement. Attached Figure Description

[0040] Figure 1This is a schematic diagram of the overall structure of Embodiment 1 of the present invention;

[0041] Figure 2 This is a schematic diagram of the cross-section of the ceramic insulating layer after trenching in Embodiment 4 of the present invention;

[0042] Figure 3 This is a top view schematic diagram of the sensor mounting slot screen printing conductive paste and sintering and curing according to Embodiment 4 of the present invention;

[0043] Figure 4 This is a top view of Embodiment 4 of the present invention, showing the placement of a temperature sensor in a sensor mounting slot;

[0044] Figure 5 This is a top view schematic diagram of Embodiment 4 of the present invention, in which ceramic slurry is filled into the sensor mounting slot and heated to cure.

[0045] Figure 6 This is a schematic diagram of the cross-section of a sensor mounting slot filled with ceramic slurry and then heated and cured according to Embodiment 4 of the present invention.

[0046] Figure 7 This is a top view schematic diagram of a through hole drilled on the surface of a ceramic insulating layer in Embodiment 4 of the present invention;

[0047] Figure 8 This is a top view schematic diagram of copper plating inside the through hole in Embodiment 4 of the present invention;

[0048] Figure 9 This is a top view schematic diagram of Embodiment 4 of the present invention, in which copper is deposited on the upper and lower surfaces of the ceramic insulating layer and then melted at high temperature to form a substrate;

[0049] Figure 10 This is a schematic diagram of the cross-section of a temperature sensor placed in a deep trench according to Embodiment 5 of the present invention;

[0050] Figure 11 This is a schematic diagram of the cross-section of a deep trench filled with ceramic slurry and heated to solidify, according to Embodiment 5 of the present invention.

[0051] Figure 12 This is a schematic diagram of the cross-section of a substrate formed by copper plating on the upper and lower surfaces of the flipped ceramic insulating layer and high-temperature melting, as described in Embodiment 5 of the present invention.

[0052] In the diagram: 1. Lower metal layer; 2. Ceramic insulating layer; 3. Temperature sensor chip; 4. Sensor mounting slot; 5. Upper metal layer; 6. Electrode; 7. Insulating filler; 8. Vertical conductive via; 9. Metal plating; 10. Conductor; 11. External pad. Detailed Implementation

[0053] The present invention will now be described in further detail with reference to the accompanying drawings. Example 1:

[0054] A packaging substrate with temperature detection function includes:

[0055] An integrally formed ceramic insulating layer 2 has a first surface and a second surface opposite to each other, the first surface being used to connect to a heat sink via a copper foil layer;

[0056] The sensor mounting groove 4 is a recessed structure formed on the second surface;

[0057] An independent temperature sensor chip 3 is housed in the sensor mounting slot 4;

[0058] The insulating filler 7 fills the gap between the temperature sensor chip 3 and the inner wall of the sensor mounting groove 4. The material of the insulating filler 7 is the same as the main material of the ceramic insulating layer 2.

[0059] And a three-dimensional interconnect structure, which is configured to lead the electrical signal of the temperature sensor chip 3 to the external pad 11 of the second surface or side of the ceramic insulating layer 2. The overall structural schematic diagram of Embodiment 1 of the present invention is shown below. Figure 1 As shown.

[0060] The three-dimensional interconnect structure includes:

[0061] The conductor 10 is disposed at the bottom or side wall of the sensor mounting slot 4 and is electrically connected to the electrode 6 of the temperature sensor chip 3.

[0062] The vertical conductive via 8 extends from the surface of the ceramic insulating layer 2 toward the conductor 10;

[0063] And an upper metal 5 formed on the surface of the ceramic insulating layer 2, the upper metal 5 being electrically connected to the conductor 10 through a vertical conductive via 8, and forming an external pad 11.

[0064] Vertical conductive via 8 is a via that is metallized by magnetron sputtering or molten metal self-filling process.

[0065] The conductor 10 is made of silver or copper paste formed by screen printing and sintering.

[0066] The ceramic insulating layer 2 is made of alumina or silicon nitride.

[0067] When the ceramic insulating layer 2 is made of alumina, the insulating filler 7 is a sintered and cured alumina ceramic slurry;

[0068] When the ceramic insulating layer 2 is made of silicon nitride, the insulating filler 7 is a sintered and cured silicon nitride ceramic slurry.

[0069] The independent sensor chip is embedded in the ceramic insulating layer through a groove, homogeneous filling and three-dimensional interconnection process, which creates a direct heat conduction channel from the chip junction, chip substrate, ceramic insulating layer and temperature sensor. Heat does not need to be conducted laterally inside the silicon wafer, so it can quickly and accurately capture the instantaneous changes in the chip junction temperature and achieve high-precision temperature feedback.

[0070] Among them, the ceramic insulating layer itself is used as the main insulating medium to undertake the high-voltage isolation task between the power chip and the embedded sensor. At the same time, the same ceramic slurry as the main material of the insulating layer is used for gap filling, forming an integrated insulating structure with matching thermal expansion coefficient and dense and bubble-free structure. This "homogeneous filling" technology ensures long-term insulation stability and reliability under high temperature and high electric field conditions, and avoids the risk of electrical short circuit between sensor electrodes and high voltage unit.

[0071] Among them, functional integration is achieved at the packaging level, decoupling the temperature sensing function from the chip manufacturing process. The laser processing, screen printing, and sintering used are all mature and efficient packaging processes that are not tied to specific chip processes, have strong compatibility, and high yield. In addition, the three-dimensional interconnect structure is more robust and reliable than connecting through fine metal interconnects on the chip surface, avoiding the risk of bonding wire detachment or other traditional packaging failures.

[0072] Independent, stable temperature sensor chips, such as thermistors, are selected. These chips have good consistency in electrothermal parameters. Furthermore, the sensors dissipate heat through efficient heat conduction paths, and the heat generated by their own power consumption has little impact on the measurement, thus ensuring the fast and accurate electrothermal response characteristics of the sensing unit. Example 2:

[0073] Power semiconductor module, including:

[0074] Packaging substrate with temperature detection function;

[0075] The power semiconductor chip is directly fixed to the surface of the upper metal 5 of the packaging substrate through a bonding layer, and at least partially overlaps with the sensor mounting groove 4 in the vertical projection, so that the heat generated by the power semiconductor chip is directly conducted to the temperature sensor chip 3 through the ceramic insulating layer 2. The bonding layer is solder or other connection structure with the same function. Example 3:

[0076] A method for manufacturing a packaging substrate with temperature detection function, comprising the following steps:

[0077] a. A sensor mounting groove 4 is formed on the second surface of the ceramic insulating layer 2;

[0078] b. A conductor 10 is formed inside the sensor mounting slot 4;

[0079] c. Install the independent temperature sensor chip 3 into the sensor mounting slot 4, and electrically connect its electrode 6 to the conductor 10.

[0080] d. Fill the gap between the temperature sensor chip 3 and the mounting groove with ceramic slurry of the same material as the ceramic insulation layer 2, and sinter and solidify it to form an insulating filler 7 integrated with the ceramic insulation layer 2;

[0081] e. Forming a vertical conductive via 8 extending from the outer surface of the ceramic insulating layer 2 to the conductor 10;

[0082] f. An upper metal layer 5 and an outer pad 11 are disposed on the surface of the ceramic insulating layer 2, and electrically interconnected with the conductor 10 through a vertical conductive via 8.

[0083] Step e includes: machining a vertically conductive via 8 from the second surface of the ceramic insulating layer 2 opposite to the first surface to expose the conductor 10; and then forming a metal plating layer 9 on the inner wall of the vertically conductive via 8 by a magnetron sputtering process.

[0084] Step e includes: processing a vertical conductive via 8 from the second surface of the ceramic insulating layer 2 using a chemical etching process, using a conductor 10 as an etching stop layer, and then metallizing the vertical conductive via 8 using a molten metal self-filling process. Example 4:

[0085] A method for manufacturing a packaging substrate with temperature detection function includes the following steps:

[0086] 1) Pretreatment of ceramic insulation layer 2: Take the alumina ceramic insulation layer 2 to be processed and use ultrasonic cleaning process. The cleaning medium is anhydrous ethanol-deionized water mixed solution. The cleaning power is 300-500W and the cleaning time is 15-20min to remove dust, oil and other impurities attached to the surface. The surface roughness is detected by laser profilometer to ensure that there are no impurities, oil and scratches on the surface.

[0087] 2) Processing of sensor mounting slot 4: Based on the preset mounting dimensions and position parameters of the temperature sensor chip 3, a laser etching process is used, employing a high-energy ultraviolet beam, to form the target slot on the surface of the pre-treated ceramic insulating layer 2 under CNC control. The dimensional tolerance of the sensor mounting slot 4 is controlled within ±0.05mm. A schematic diagram of the cross-section of the ceramic insulating layer 2 after slotting in Embodiment 4 of this invention is shown below. Figure 2 As shown.

[0088] 3) Preparation of conductor 10: Silver powder, glass powder, ethyl cellulose, and terpineol are mixed in a mass ratio of 90:5:3:2 and dispersed in a ball mill to prepare a conductive paste with a solid content of 75%-80%. Using screen printing, the silver paste is precisely coated onto the preset conductive area of ​​the sensor mounting slot 4 at a doctor blade pressure of 10 N / cm² and a printing speed of 50 mm / s, controlling the wet film thickness to 5-20 μm. Subsequently, the ceramic insulating layer 2 coated with silver paste is placed in a sintering furnace and sintered and cured under an inert gas atmosphere according to the heating curve. The heating rate is 5℃ / min, reaching 300℃ and holding for 30 min, then increasing to 450℃ at 2℃ / min and holding for 60 min, followed by a cooling rate of 3℃ / min to room temperature. A top view of the screen-printed conductive paste and sintered and cured sensor mounting slot 4 in Embodiment 4 of this invention is shown below. Figure 3 As shown.

[0089] 4) Temperature sensor chip 3 installation: Take the temperature sensor chip 3 and accurately install it in the sensor mounting slot 4 using a positioning fixture. Connect the sensor electrode 6 to the conductor 10. Then, place the assembled assembly on a heating platform and heat it at 80-120℃ for 15-30 minutes to complete the electrical connection between the temperature sensor chip 3 and the conductor 10. A top view of embodiment four of this invention showing the temperature sensor placed in the sensor mounting slot 4 is shown below. Figure 4 As shown.

[0090] 5) Gap Filling and Curing: An alumina ceramic slurry, i.e., the insulating filler 7, is prepared. 0.5% B2O3 is added to the ceramic slurry as an activator. The ceramic slurry is then filled into the gap between the sensor mounting groove 4 and the temperature sensor chip 3 using a dispensing process, ensuring complete filling without air bubbles. The filled component is placed in a sintering furnace for step curing: 80℃ for 60 min, 150℃ for 40 min, and 300℃ for 30 min. After curing, the volume shrinkage rate of the ceramic slurry is ≤2%, and it forms a tight bond with the ceramic insulating layer 2 and the sensor surface. The top view and cross-sectional view of the ceramic slurry filling and curing process in Embodiment 4 of this invention are shown below. Figures 5-6 As shown.

[0091] 6) Machining of vertical conductive through-hole 8: Based on the position coordinates of conductor 10, a mechanical drilling process is used to physically cut the ceramic insulating layer 2 with a diamond-coated or carbide end mill via CNC milling to machine a vertical conductive through-hole 8 on the surface of the ceramic insulating layer 2. The diameter of the vertical conductive through-hole 8 is controlled between 0.1-0.3 mm. One end of the vertical conductive through-hole 8 is connected to conductor 10, and the other end penetrates to the outer surface of the ceramic insulating layer 2. A top view of the through-hole drilling on the surface of the ceramic insulating layer 2 in Embodiment 4 of the present invention is shown below. Figure 7 As shown.

[0092] 7) Through-hole metallization and electrical connection: The ceramic insulating layer 2 with vertical conductive through-holes 8 is placed in the vacuum chamber of a magnetron sputtering device. Using copper as the target material, magnetron sputtering is performed on the inner wall of the through-hole and the surface of the ceramic insulating layer 2 under sputtering power of 100-300W to form a metal plating layer 9. The temperature sensor chip 3 and the surface of the ceramic insulating layer 2 are electrically connected through this copper plating layer. A top view of copper plating in the through-hole in Embodiment 4 of the present invention is shown below. Figure 8 As shown.

[0093] 8) Substrate Forming: Take copper sheets as the upper metal layer 5 and the lower metal layer 1, with a thickness of 0.1-0.5 mm and a surface roughness of less than 0.8 μm, and coat them onto the upper and lower surfaces of the ceramic insulating layer 2, respectively, ensuring that the copper sheets are tightly bonded to the surface of the ceramic insulating layer 2. Place the copper-coated component in a high-temperature melting furnace and heat it at 700-850℃ for 20-40 minutes under an inert gas protective atmosphere to achieve a eutectic melt at the interface between the copper sheets and the ceramic insulating layer 2. After cooling, the substrate is formed, and the electrical interconnection between the positive and negative electrodes of the sensor and the external pads 11 is completed. The external pads 11 are PADs. The top view schematic diagrams of the copper coating and high-temperature melting on the upper and lower surfaces of the ceramic insulating layer 2 to form the substrate in Embodiment 4 of this invention are shown below. Figure 9 As shown. Example 5:

[0094] A method for manufacturing a packaging substrate with temperature detection function includes the following steps:

[0095] A. Pretreatment of ceramic insulation layer 2: Take the silicon nitride ceramic insulation layer 2 to be processed and use ultrasonic cleaning process. The cleaning medium is anhydrous ethanol-deionized water mixed solution. The cleaning power is 300-500W and the cleaning time is 15-20min to remove dust, oil and other impurities attached to the surface. The surface roughness is detected by laser profilometer to ensure that there are no impurities, oil and scratches on the surface.

[0096] B. Machining of sensor mounting slot 4: Based on the preset mounting dimensions and position parameters of temperature sensor chip 3, a mechanical machining process is adopted. Using a diamond-coated or carbide end mill, a CNC milling cutter is used to physically cut the ceramic insulation layer 2 to machine the sensor mounting slot 4 on the surface of the ceramic insulation layer 2. The dimensional tolerance of the sensor mounting slot 4 is controlled within ±0.05mm.

[0097] C. Preparation of Conductor 10: Copper powder, glass powder, ethyl cellulose, and terpineol are mixed in a mass ratio of 90:5:3:2 and dispersed in a ball mill to prepare a conductive paste with a solid content of 75%-80%. Using a screen printing process, the copper paste is precisely coated onto the preset conductive area of ​​the sensor mounting groove 4 at a doctor blade pressure of 10 N / cm² and a printing speed of 50 mm / s, controlling the wet film thickness to 5-20 μm. Subsequently, the ceramic insulating layer 2 coated with copper paste is placed in a sintering furnace and sintered and cured according to a heating curve under an inert gas protective atmosphere. The heating rate is 5℃ / min, reaching 300℃ and holding for 30 min, then increasing to 450℃ at 2℃ / min and holding for 60 min, followed by a cooling rate of 3℃ / min to room temperature. A schematic diagram of the cross-section of the temperature sensor placed in the deep groove in Embodiment 5 of this invention is shown below. Figure 10 As shown.

[0098] D. Temperature sensor chip 3 installation: Take the temperature sensor chip 3 and accurately install it in the sensor mounting slot 4 using a positioning fixture. Connect the sensor electrode 6 to the conductor 10. Then place the assembled component on a heating platform and heat it at 80-120℃ for 15-30 minutes to complete the electrical connection between the temperature sensor chip 3 and the conductor 10.

[0099] E. Gap Filling and Curing: A silicon nitride ceramic slurry, i.e., insulating filler 7, is prepared, and 0.5% SiO2 is added to the ceramic slurry as an activator. The ceramic slurry is filled into the gap between the sensor mounting groove 4 and the temperature sensor chip 3 using a dispensing process, ensuring that the gap is completely filled without air bubbles. The filled component is placed in a sintering furnace for step curing: 80℃ for 60 min, 150℃ for 40 min, and 300℃ for 30 min. After curing, the volume shrinkage rate of the ceramic slurry is ≤2%, and it forms a tight bond with the ceramic insulating layer 2 and the sensor surface. The cross-sectional schematic diagram of filling the deep groove with ceramic slurry and heating for curing in Embodiment 5 of this invention is shown below. Figure 11 As shown.

[0100] F. Processing of Vertical Conductive Through-Hole 8: The ceramic insulating layer 2 is flipped over. Based on the position coordinates of the conductor 10, a self-stopping process is used. Based on the position coordinates of the conductor 10, the surface of the ceramic insulating layer 2 is patterned by photolithography. Then, a chemical etching process is used to etch the ceramic insulating layer 2 to process the vertical conductive through-hole 8. The etchant used in the chemical etching process is a mixed solution of dilute nitric acid and hydrofluoric acid, which has a selective corrosion effect on ceramic materials but does not corrode the conductor 10. When etching reaches the surface of the conductor 10, a self-stopping effect is formed due to the corrosion resistance of the conductor 10 to the etchant, ensuring that one end of the vertical conductive through-hole 8 is precisely connected to the conductor 10, and the other end penetrates to the outer surface of the ceramic insulating layer 2.

[0101] G. Through-hole metallization and substrate forming: A self-filling process is adopted. By completely attaching the copper foil to the opening end of the vertical conductive through-hole 8 of the ceramic insulating layer 2 and the chip mounting position, the ceramic insulating layer 2 covered with copper foil is placed in a nitrogen gas protective atmosphere. After heating under high pressure, the copper foil melts to form liquid copper. Under the action of thermal driving force, the liquid copper flows along the inner wall of the vertical conductive through-hole 8 and fills the entire cavity of the vertical conductive through-hole 8 until the interior of the vertical conductive through-hole 8 is completely filled with copper. Then, heating is stopped, and the ceramic insulating layer 2 is cooled to room temperature with the furnace. The liquid copper solidifies in the vertical conductive through-hole 8 to form a solid copper pillar. One end of the copper pillar is metallurgically bonded to the conductor 10 and maintains electrical conductivity. The other end is integrally connected to the residual copper layer at the opening end of the vertical conductive through-hole 8, thereby completing the conductive filling of the vertical conductive through-hole 8. The positive and negative electrodes 6 of the sensor are connected to the external pad 11 to complete the substrate fabrication. The external pad 11 is a PAD. The cross-sectional diagram of the substrate formed by copper coating on the upper and lower surfaces of the flipped ceramic insulating layer 2 and high-temperature melting is shown in the figure below. Figure 12 As shown.

[0102] In Embodiment 5, a vertical conductive through hole 8 is drilled on the other side of the opening of the sensor mounting slot 4. The electrical isolation between the temperature sensor chip 3 and the semiconductor chip 10 mounted on the upper metal layer 5 is achieved by the ceramic insulating layer 2. The ceramic slurry used to fill the sensor mounting slot 4 does not need to be selected from high-purity, high-density or high-quality ceramic raw materials with specific performance parameters. It only needs to meet the basic requirements of formability and filling density to be suitable for the filling scenario of the sensor mounting slot 4.

[0103] The ceramic insulating layer 2 can be made of materials including but not limited to alumina, aluminum nitride, boron nitride, magnesium oxide, silicon nitride, beryllium oxide, glass ceramics, SiC-based composite materials, multilayer gradient ceramics, and other emerging high-performance materials, with thermal conductivity much greater than 1 W / m·K.

[0104] The pretreatment of the ceramic insulation layer 2 includes, but is not limited to, multi-stage ultrasonic cleaning, plasma activation treatment, precision drying, surface planarization treatment and three-dimensional inspection, to ensure that the surface of the ceramic insulation layer 2 is free of impurities, oil stains and scratches, and to meet the accuracy requirements of subsequent processing.

[0105] Among them, the ceramic substrate cavity processing technology used in the manufacturing of sensor mounting slot 4 includes, but is not limited to, laser processing, precision mechanical milling, ultrasonic-assisted processing, and chemical etching processing. Laser processing can use ultraviolet laser or CO2 laser focused on the ceramic surface to remove material through photothermal ablation or photochemical decomposition. Precision mechanical milling process uses diamond-coated carbide tools for high-speed rotary cutting, and is combined with coolant to reduce edge chipping.

[0106] The conductor 10 is prepared by first preparing a conductive paste, which may include, but is not limited to, silver paste, copper paste, gold paste, aluminum paste, nickel paste, palladium paste, platinum paste, and graphite paste. The paste is then precisely applied to the preset conductive area using screen printing and cured by heating to form the conductor 10.

[0107] The conductor 10 is prepared by preparing a barrier layer conductive paste, including but not limited to titanium, titanium nitride, tantalum, tantalum nitride, molybdenum, molybdenum nitride, and other barrier layer conductive pastes. The barrier layer conductive paste is first precisely coated onto the preset conductive area of ​​the sensor mounting groove 4 by screen printing, and then heated and cured. After the conductive paste is applied and heated and cured to form the conductor 10, another layer of barrier layer conductive paste is applied to the conductor 10 by screen printing, and then heated and cured. The barrier layer metal can prevent the mutual diffusion between the conductor 10 and the ceramic insulating layer 2, avoid the formation of unwanted compounds or defects, and at the same time improve the adhesion between the conductor 10 and the ceramic insulating layer 2, and enhance the stability of the structure.

[0108] In the gap filling and curing process, ceramic powder is used as aggregate, sodium silicate as binder, and deionized water as solvent to prepare a ceramic slurry. This slurry is homogenized using a high-speed disperser and then injected into the gap between the sensor mounting slot 4 and the temperature sensor chip 3 using a scraping or dispensing process, ensuring no air bubbles or voids. The slurry is then placed in a sintering furnace for step curing, resulting in a tight bond between the slurry and the ceramic insulating layer 2 and the sensor surface.

[0109] Heating the ceramic slurry to solidify it can reduce the required solidification temperature by adding an activator or applying pressure to the ceramic slurry, thus avoiding the solidification temperature from approaching or even exceeding the tolerance limit of the temperature sensor chip 3, which could lead to performance degradation, structural damage, or direct burnout of the temperature sensor chip 3. The activator materials include, but are not limited to, phosphate activators and borate glass.

[0110] In this process, through-hole processing can be performed by drilling holes on the back of the ceramic insulating layer 2. The electrical isolation between the temperature sensor chip 3 and the upper metal 5 is achieved by the ceramic insulating layer 2. The ceramic slurry used to fill the sensor mounting slot 4 does not need to be made of high-pressure resistant material.

[0111] Among them, through-hole processing can be carried out by mechanical processing. Based on the position coordinates of conductor 10, the ceramic insulating layer 2 is physically cut by CNC milling with diamond-coated or carbide end mills to form the target groove.

[0112] The through-hole processing can employ a self-stopping process. Based on the position coordinates of the conductor 10, the surface of the ceramic insulating layer 2 is patterned using photolithography. Subsequently, a chemical etching process is used to etch the ceramic insulating layer 2 to process the vertical conductive through-hole 8. The etchant used in the chemical etching process has a selective corrosion effect on ceramic materials, while it does not corrode the conductor 10 or has a low corrosion rate. When etching reaches the surface of the conductor 10, a self-stopping effect is formed due to the corrosion resistance of the conductor 10 to the etchant. This ensures that one end of the vertical conductive through-hole 8 is precisely connected to the conductor 10, while the other end extends to the outer surface of the ceramic insulating layer 2. This avoids the problems of uncontrolled through-hole depth, inaccurate reaching of the conductor 10, or excessive etching that can damage the conductor 10 that are prone to occur in mechanical etching.

[0113] Among them, through-hole metallization adopts a conductive paste sintering process. After the conductive paste is fully stirred, it is filled into the through-hole by screen printing and then sintered and cured in an atmosphere sintering furnace. Alternatively, a magnetron sputtering method is used to sputter a copper target into the through-hole to form a copper pillar.

[0114] The through-hole metallization can be achieved using a self-filling process. This involves completely bonding a copper foil to the opening of the vertical conductive through-hole 8, placing the ceramic insulating layer 2 covered with the copper foil in an inert gas protective atmosphere, and heating it under high pressure to melt the copper foil into liquid copper. Under the action of thermal driving force, the liquid copper flows along the inner wall of the vertical conductive through-hole 8 and fills the entire cavity of the vertical conductive through-hole 8 until the interior of the vertical conductive through-hole 8 is completely filled with copper. Then, heating is stopped, and the ceramic insulating layer 2 is cooled to room temperature with the furnace. The liquid copper solidifies in the vertical conductive through-hole 8 to form a solid copper pillar. One end of the copper pillar is metallurgically bonded to the conductor 10 and maintains electrical conductivity, while the other end is integrally connected to the residual copper layer at the opening of the vertical conductive through-hole 8, thereby completing the conductive filling of the vertical conductive through-hole 8. The self-filling process simplifies the substrate process steps and eliminates the need for through-hole metallization.

[0115] The lower metal layer 1 and the upper metal layer 5 can be connected to the ceramic insulating layer 2 through various processes, such as direct copper plating and active metal brazing.

[0116] Working principle:

[0117] By embedding the temperature sensor within the ceramic insulating layer 2 using a fabrication method compatible with existing processes, the heat transfer path to the sensor can be significantly shortened, reducing path losses during heat transfer and thus significantly improving heat transfer efficiency. This allows the sensor to accurately capture temperature changes at the top of the substrate. When the temperature sensor is directly coupled to the high thermal conductivity ceramic substrate, heat transfer is not achieved without the use of organic thermally conductive adhesive, eliminating the thermal attenuation problem caused by the thermally conductive adhesive layer in traditional solutions. This ensures that heat can be directly and efficiently transferred to the sensor. At the same time, this integrated architecture avoids the defects of organic thermally conductive adhesive materials that are prone to thermal aging under long-term high-temperature environments, which leads to increased thermal resistance and deterioration of heat transfer performance, ensuring the long-term stability of temperature monitoring. In addition, the ceramic insulating layer 2 itself has excellent insulation properties, which can effectively isolate electromagnetic interference generated by other electrical components inside the module, avoiding the influence of interference signals on the sensor's temperature measurement signal, greatly improving the accuracy of temperature measurement, and reducing the module area to a certain extent.

[0118] The beneficial effects of this invention are that the packaging substrate can achieve high-precision and fast-response measurement of the junction temperature of power chips, eliminate temperature rise decoupling deviation, ensure excellent high-voltage electrical isolation reliability while achieving direct thermal coupling, avoid the risk of dielectric breakdown, and its manufacturing method is flexible, improving the reliability of power semiconductor modules, reducing overall costs, ensuring the fast and accurate electrothermal response characteristics of the sensing unit, and ensuring the long-term stability of temperature monitoring.

[0119] The foregoing has provided a detailed description of one embodiment of the present invention, but this description is merely a preferred embodiment and should not be construed as limiting the scope of the invention. All equivalent variations and modifications made within the scope of the claims of this invention should still fall within the patent coverage of this invention.

Claims

1. A method for manufacturing a packaging substrate with temperature detection function, characterized in that, Includes the following steps: a. A sensor mounting groove (4) is formed on the second surface of the ceramic insulating layer (2); b. A conductor (10) is formed in the sensor mounting slot (4); c. Install the independent temperature sensor chip (3) into the sensor mounting slot (4) and electrically connect its electrodes to the conductor (10); d. Fill the gap between the temperature sensor chip (3) and the mounting groove with ceramic slurry of the same material as the ceramic insulation layer (2), and fill the sensor mounting groove (4). Sintering is carried out by adding activator or pressurizing to reduce the temperature required for sintering and solidification, forming an integrated insulating filler (7) with the same material as the ceramic insulation layer and a matching coefficient of thermal expansion. e. The vertical conductive via (8) extending from the outer surface of the ceramic insulating layer (2) to the conductor (10) is metallized by magnetron sputtering or molten metal self-filling process; f. An upper metal (5) is disposed on the surface of the ceramic insulating layer (2) and heated to achieve a eutectic melt at the interface between the two. The upper metal (5) is electrically connected to the conductor (10) through the vertical conductive through hole (8). The upper metal (5) forming the electrical connection constitutes the external pad (11), realizing the electrical interconnection between the sensor electrode and the external pad (11).

2. A packaging substrate with temperature detection function, characterized in that, include: It is manufactured using the method described in claim 1. An integrally formed ceramic insulating layer (2) has a first surface and a second surface opposite to each other, the first surface being connected to the heat sink via a copper foil layer; The sensor mounting groove (4) is a recessed structure formed on the second surface; An independent temperature sensor chip (3) is housed in the sensor mounting slot (4); An insulating filler (7) is used to fill the gap between the temperature sensor chip (3) and the inner wall of the sensor mounting groove (4). The material of the insulating filler (7) is the same as the main material of the ceramic insulating layer (2). And a three-dimensional interconnect structure configured to direct the electrical signals of the temperature sensor chip (3) to the external pads (11) of the second surface of the ceramic insulating layer (2). The ceramic insulating layer (2) is made of alumina or silicon nitride; When the ceramic insulating layer (2) is made of alumina, the insulating filler (7) is a sintered and cured alumina ceramic slurry; When the ceramic insulating layer (2) is made of silicon nitride, the insulating filler (7) is a sintered and cured silicon nitride ceramic slurry; The three-dimensional interconnect structure includes: A conductor (10) is disposed at the bottom or side wall of the sensor mounting slot (4), and the conductor (10) is electrically connected to the electrode (6) of the temperature sensor chip (3). The vertical conductive via (8) extends from the surface of the ceramic insulating layer (2) toward the conductor (10); And an upper metal (5) formed on the surface of the ceramic insulating layer (2), the upper metal (5) being electrically connected to the conductor (10) through the vertical conductive via (8) and forming the outer pad (11).

3. A power semiconductor module, characterized in that, include: The packaging substrate with temperature detection function as described in claim 2; The power semiconductor chip is directly fixed to the surface of the upper metal (5) of the packaging substrate through a bonding layer and at least partially overlaps with the sensor mounting groove (4) in vertical projection, so that the heat generated by the power semiconductor chip is directly conducted to the temperature sensor chip (3) through the ceramic insulating layer (2).

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