Packaging process of a temperature sensor chip

Abstract

A packaging process for a temperature sensor chip includes the following steps: selecting an aluminum nitride ceramic substrate and choosing a gold-tin solder sheet of corresponding size according to the chip size; cleaning the aluminum nitride ceramic substrate; fabricating a double-sided metallization layer on the aluminum nitride ceramic substrate; cutting the aluminum nitride ceramic substrate with the deposited metallization layer according to the chip size; placing a metal casing on a sintering mold; placing a gold-tin solder sheet on the metal casing; placing the cut aluminum nitride ceramic substrate on the gold-tin solder sheet; placing another gold-tin solder sheet on the aluminum nitride ceramic substrate; finally placing the chip; and placing them together in a eutectic bonding furnace for sintering; using a programmable vacuum eutectic bonding furnace for eutectic sintering; after welding, waiting for the temperature to drop below 70°C, opening the chamber door, and removing the device. The advantages are: high temperature sensing performance, good insulation effect, reasonable process, simple operation, high production efficiency, and suitability for industrial production.

Description

Technical Field

[0001] This invention relates to a packaging process, and more particularly to a packaging process for a temperature sensor chip. Background Technology

[0002] As is well known, temperature sensor chips are high-precision chips with very fast response times. Since the primary function of a temperature sensor chip is temperature sensing, it must have a good temperature transmission path with the casing during packaging. Eutectic bonding significantly reduces the thermal resistance between the chip and the casing, but the inherent properties of the chip prevent it from being directly connected to a metal casing. Currently, temperature sensor chips typically use insulating adhesive bonding, meaning the chip and casing are bonded together with insulating adhesive, which greatly reduces thermal conductivity. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide a packaging process for a temperature sensor chip that not only has high temperature sensing performance and good insulation effect, but also has a reasonable process, simple operation, and high production efficiency, making it suitable for industrial production.

[0004] To achieve the above objectives, the present invention adopts the following technical solution:

[0005] A packaging process for a temperature sensor chip includes the following steps:

[0006] 1. Select an aluminum nitride ceramic substrate and choose the corresponding size of gold-tin solder sheet according to the size of the chip;

[0007] 2. Cleaning of aluminum nitride ceramic substrates;

[0008] 3. Fabricate the metallization layer on the aluminum nitride ceramic substrate;

[0009] 3.1 Select a magnetron sputtering stage with four target positions and deposit a composite metal layer by sputtering; place the aluminum nitride ceramic substrate in a tray and send it into the sputtering chamber of the magnetron sputtering stage, and heat the substrate to a temperature of 160℃±10℃.

[0010] 3.2 Then, the aluminum nitride ceramic substrate is subjected to reverse sputtering. The aluminum nitride ceramic substrate is bombarded at a power of 150W±10W for 300s±10s to remove the contamination layer on the substrate surface, activate the substrate surface, and improve the adhesion of the sputtered film layer on the substrate surface.

[0011] 3.3. Sputtering a CrSi-NiCr-Au composite film on the substrate surface: First, sputter the CrSi layer at a power of 100W±10W for 500s±10s and an argon flow rate of 13sccm±2sccm. During sputtering, the high-pressure valve was shut off to partially close the vacuum channel, and then the oxygen flow meter was turned on to introduce a certain amount of oxygen for reactive sputtering at a flow rate of 3sccm±1sccm. Immediately after sputtering the CrSi layer, the NiCr film was sputtered at a power of 300W±10W for 300s±10s. Finally, the Au layer was sputtered at a power of 200W±10W for 300s±10s. After sputtering, the aluminum nitride ceramic substrate was removed, and the other side was sputtered using the same method to form a CrSi-NiCr-Au composite metallization layer on both sides of the substrate.

[0012] 4. Cut the aluminum nitride ceramic substrate with the metallized layer deposited according to the size of the chip. Then place the metal shell on the sintering mold, place the gold-tin solder sheet on the metal shell, place the cut aluminum nitride ceramic substrate on the gold-tin solder sheet, place the gold-tin solder sheet on the aluminum nitride ceramic substrate again, and finally place the chip; and put them together in the eutectic bonding furnace for sintering.

[0013] 5. Use a programmable vacuum eutectic bonding furnace for eutectic sintering. After the welding is completed, wait for the temperature to drop below 70°C, then open the chamber door and remove the device.

[0014] 6. Finally, the eutectic sintered product is bonded and capped to complete the encapsulation.

[0015] As a further preferred embodiment, the aluminum nitride ceramic substrate has a thickness of 0.3±0.02mm and a thermal conductivity ≥170W / m·k.

[0016] As a further preferred option, the aluminum nitride ceramic substrate is first ultrasonically cleaned with acetone for 15 minutes, then rinsed with deionized water, and finally dehydrated with anhydrous ethanol, dried with nitrogen, and then dried with an oven lamp for later use.

[0017] As a further preferred option, the steps for eutectic sintering are as follows:

[0018] (1) First, evacuate the vacuum chamber and fill it with nitrogen to purify the atmosphere inside the vacuum chamber; then start heating to bring the temperature inside the furnace to 180℃±10℃. At this time, formic acid is introduced, and the flow rate is controlled at the maximum value of 8s lm~10s lm. The formic acid decomposes upon heating to produce hydrogen. The hydrogen neutralizes the oxygen in the vacuum chamber and provides the reducing gas required for welding. The mold and the shell are preheated.

[0019] (2) Continue to heat up to 280℃±10℃ and hold the temperature for 200s~300s to fully preheat the mold and the shell, in preparation for the melting of the solder eutectic.

[0020] (3) After the constant temperature is completed, the temperature is rapidly increased to 350℃±10℃ within 100s±10s, and the temperature is kept constant for 50s±10s to melt the gold-tin solder sheet and end the eutectic process.

[0021] (4) Turn off the formic acid flow, evacuate the vacuum chamber and remove the remaining formic acid; then turn off the heating and fill with nitrogen to cool down.

[0022] The beneficial effects of this invention are as follows:

[0023] 1. The process is reasonable and the operation is simple. By selecting aluminum nitride ceramic substrates with high thermal conductivity, ceramic metallization treatment is carried out on them using sputtering process. CrSi-NiCr-Au composite film metallization layer is selected, and oxygen is introduced during the sputtering of the first CrSi layer. Through the combination of oxygen with the incident deposited atoms, an oxide intermediate layer is generated, which can enhance the adhesion of the film.

[0024] 2. During eutectic sintering, a programmable vacuum eutectic bonding furnace is selected, and a double-layer gold-tin solder sheet is used for eutectic sintering. By cleverly and reasonably modifying the eutectic sintering process, editing the eutectic curve, and increasing the isothermal time of the preheating section, the double-layer gold-tin solder sheet can complete the eutectic sintering. This temperature sensor chip packaging process not only has high temperature sensing performance and good insulation effect, but also has high production efficiency, is suitable for industrial production, and can improve the quality and reliability of products. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the structure of the aluminum nitride ceramic substrate after metallization according to the present invention.

[0026] Figure 2 This is a schematic cross-sectional view of the chip, aluminum nitride ceramic substrate, and casing after eutectic sintering according to the present invention.

[0027] Figure 3 This is a top view schematic diagram of the chip, aluminum nitride ceramic substrate and casing after eutectic sintering of the present invention.

[0028] In the diagram: 1. Aluminum nitride ceramic substrate; 2. Metallization layer; 3. Chip; 4. Gold-tin solder sheet; 5. Tube shell. Detailed Implementation

[0029] The following describes in detail embodiments of the present invention, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0030] Example 1

[0031] Reference Figures 1-3 As shown, the present invention relates to a packaging process for a temperature sensor chip, comprising the following steps:

[0032] 1. Select aluminum nitride ceramic substrate 1, and select gold-tin solder sheet 4 of corresponding size according to the size of the chip; the thickness of aluminum nitride ceramic substrate 1 is 0.3±0.02mm, and the thermal conductivity is ≥170W / m·k.

[0033] 2. Cleaning of aluminum nitride ceramic substrate 1: When cleaning the aluminum nitride ceramic substrate 1, first use acetone for ultrasonic cleaning for 15 minutes, then rinse with deionized water, finally dehydrate with anhydrous ethanol, blow dry with nitrogen, and dry with an oven lamp for later use.

[0034] 3. Fabricate the metallization layer of aluminum nitride ceramic substrate 1;

[0035] 3.1 Select a magnetron sputtering stage with four target positions and deposit a composite metal layer by sputtering. Place the aluminum nitride ceramic substrate 1 in a tray and send it into the sputtering chamber of the magnetron sputtering stage. Heat the substrate to a temperature of 160℃±10℃.

[0036] 3.2 Then, the aluminum nitride ceramic substrate 1 is subjected to reverse sputtering. The aluminum nitride ceramic substrate 1 is bombarded at a power of 150W±10W for 300s±10s to remove the contamination layer on the substrate surface, activate the substrate surface, and improve the adhesion of the sputtered film layer on the substrate surface.

[0037] 3.3. A CrSi-NiCr-Au composite film is sputtered onto the surface of the aluminum nitride ceramic substrate 1. First, a CrSi layer is sputtered, with the power set at 100W±10W and the time at 500s±10s. Argon gas flow rate is 13sccm±2sccm. During sputtering, the high-pressure valve is first shut off to partially close the vacuum channel. Then, the oxygen flow meter switch is turned on to introduce a certain amount of oxygen for reaction sputtering. The oxygen flow rate is 3sccm±1sccm. The oxygen reacts with the incident... Depositing atomic phases to form an oxide intermediate layer enhances the adhesion of the thin film. Immediately after sputtering the CrSi layer, a NiCr film is sputtered at a power of 300W ± 10W for 300s ± 10s. Finally, an Au layer is sputtered at a power of 200W ± 10W for 300s ± 10s. After sputtering, the aluminum nitride ceramic substrate 1 is removed, and the other side is sputtered using the same method, resulting in a CrSi-NiCr-Au composite metallization layer 2 on both sides of the substrate. Figure 1 As shown.

[0038] 4. Cut the aluminum nitride ceramic substrate 1 after the metallization layer 2 has been deposited into the size of the temperature sensing chip 3 to be packaged. Then place the metal shell 5 on the sintering mold, place the gold-tin solder sheet 4 on the metal shell 5, place the cut aluminum nitride ceramic substrate 1 on the gold-tin solder sheet 4, place the gold-tin solder sheet 4 on the aluminum nitride ceramic substrate 1 again, and finally place the chip 3. Then put them together in the eutectic bonding furnace for sintering.

[0039] 5. Use a programmable vacuum eutectic bonding furnace for eutectic sintering. After welding, wait for the temperature to drop below 70℃, open the chamber door, and remove the eutecticized components. Figure 2 and Figure 3 As shown. Under a 30-60x microscope, the solder of the product with good eutectic bonding is well wetted, and there are no holes around the chip 3. The eutectic sintering of the temperature sensing chip 3, the aluminum nitride ceramic metallization substrate, and the shell 5 can then be completed, thus completing the temperature sensor chip packaging process.

[0040] The steps for eutectic sintering are as follows:

[0041] (1) First, evacuate the vacuum chamber and fill it with nitrogen for more than 80 seconds each time. Repeat this cycle twice to purify the atmosphere in the vacuum chamber. Then, start heating to bring the furnace temperature to 180℃±10℃. At this time, formic acid is introduced and the flow rate is controlled at the maximum value of 8s lm~10s lm. The formic acid decomposes upon heating to produce hydrogen. The hydrogen neutralizes the oxygen in the vacuum chamber and provides the reducing gas - hydrogen - required for welding. The mold and tube shell 5 are preheated.

[0042] (2) Continue to heat up to 280℃±10℃ and hold the temperature for 200s~300s to fully preheat the mold and the shell 5 in preparation for the melting of the solder eutectic.

[0043] (3) After the constant temperature is completed, the temperature is rapidly increased to 350℃±10℃ within 100s±10s, and the temperature is kept constant for 50s±10s to melt the gold-tin solder sheet 4 and the eutectic process is completed.

[0044] (4) Turn off the formic acid flow, evacuate the vacuum chamber and remove the remaining formic acid; then turn off the heating and fill with nitrogen to cool down.

[0045] 6. Finally, the product after eutectic sintering is bonded with gold wire ball bonding machine, and then sealed with energy storage welding machine to complete the packaging of temperature sensor chip.

[0046] Example 2

[0047] Reference Figures 1-3 As shown, the present invention relates to a packaging process for a temperature sensor chip, comprising the following steps:

[0048] 1. Select aluminum nitride ceramic substrate 1, and select gold-tin solder sheet 4 of corresponding size according to the size of chip 3; the thickness of aluminum nitride ceramic substrate 1 is 0.3±0.02mm, and the thermal conductivity is ≥170W / m·k.

[0049] 2. Cleaning of aluminum nitride ceramic substrate 1: When cleaning the aluminum nitride ceramic substrate 1, first use acetone for ultrasonic cleaning for 15 minutes, then rinse with deionized water, finally dehydrate with anhydrous ethanol, blow dry with nitrogen, and dry with an oven lamp for later use.

[0050] 3. Fabricate the metallization layer of aluminum nitride ceramic substrate 1;

[0051] 3.1 Select a magnetron sputtering stage with four target positions and deposit a composite metal layer by sputtering; place the aluminum nitride ceramic substrate 1 in a tray and send it into the sputtering chamber of the magnetron sputtering stage, and heat the substrate to a temperature of 150°C;

[0052] 3.2 Then, the aluminum nitride ceramic substrate 1 is subjected to reverse sputtering. The aluminum nitride ceramic substrate 1 is bombarded at a power of 140W for 290s to remove the contamination layer on the substrate surface, activate the substrate surface, and improve the adhesion of the sputtered film layer on the substrate surface.

[0053] 3.3. A CrSi-NiCr-Au composite film is sputtered onto the surface of the aluminum nitride ceramic substrate 1. First, the CrSi layer is sputtered at a power of 90W for 490s with an argon flow rate of 11sccm. During sputtering, the high-pressure valve is first shut off to partially close the vacuum channel, and then the oxygen flow meter is turned on to introduce a certain amount of oxygen for reactive sputtering at a flow rate of 2sccm. The oxygen combines with the incident deposited atoms to form an oxide intermediate layer, which enhances the adhesion of the film. Immediately after sputtering the CrSi layer, the NiCr film is sputtered at a power of 290W for 290s. Finally, the Au layer is sputtered at a power of 190W for 290s. After sputtering, the aluminum nitride ceramic substrate 1 is removed, and the other side is sputtered using the same method to form a CrSi-NiCr-Au composite metallization layer 2 on both sides of the substrate. Figure 1 As shown.

[0054] 4. Cut the aluminum nitride ceramic substrate 1 after the metallization layer 2 has been deposited into the size of the temperature sensing chip to be packaged. Then place the metal shell 5 on the sintering mold, place the gold-tin solder sheet 4 on the metal shell 5, place the cut aluminum nitride ceramic substrate 1 on the gold-tin solder sheet 4, place the gold-tin solder sheet 4 on the aluminum nitride ceramic substrate 1 again, and finally place the chip 3. Then put them together in the eutectic bonding furnace for sintering.

[0055] 5. Use a programmable vacuum eutectic bonding furnace for eutectic sintering. After welding, wait for the temperature to drop below 70℃, open the chamber door, and remove the eutecticized components. Figure 2 and Figure 3 As shown. Under a 30-60x microscope, the solder of the product with good eutectic bonding is well wetted, and there are no holes around the chip 3. The eutectic sintering of the temperature sensing chip 3, the aluminum nitride ceramic metallization substrate, and the shell 5 can then be completed, thus completing the temperature sensor chip packaging process.

[0056] The steps for eutectic sintering are as follows:

[0057] (1) First, evacuate the vacuum chamber and fill it with nitrogen for more than 80 seconds each time. Repeat this cycle twice to purify the atmosphere inside the vacuum chamber. Then, start heating to bring the furnace temperature to 170°C. At this time, formic acid is introduced and the flow rate is controlled at the maximum value of 8 s lm. The formic acid decomposes upon heating to produce hydrogen. The hydrogen neutralizes the oxygen in the vacuum chamber and provides the reducing gas required for welding - hydrogen. The mold and the shell 5 are preheated.

[0058] (2) Continue to heat up to 270℃ and hold the temperature for 300s to fully preheat the mold and shell 5, in preparation for the melting of the solder eutectic.

[0059] (3) After the constant temperature is completed, the temperature is rapidly increased to 340℃ within 90s, and then kept constant for 60s to melt the gold-tin solder sheet 4, thus ending the eutectic process.

[0060] (4) Turn off the formic acid flow, evacuate the vacuum chamber and remove the remaining formic acid; then turn off the heating and fill with nitrogen to cool down.

[0061] 6. Finally, the product after eutectic sintering is bonded with gold wire ball bonding machine, and then sealed with energy storage welding machine to complete the packaging of temperature sensor chip.

[0062] Example 3

[0063] Reference Figures 1-3 As shown, the present invention relates to a packaging process for a temperature sensor chip, comprising the following steps:

[0064] 1. Select aluminum nitride ceramic substrate 1, and select gold-tin solder sheet 4 of corresponding size according to the size of chip 3; the thickness of aluminum nitride ceramic substrate 1 is 0.3±0.02mm, and the thermal conductivity is ≥170W / m·k.

[0065] 2. Cleaning of aluminum nitride ceramic substrate 1: When cleaning the aluminum nitride ceramic substrate 1, first use acetone for ultrasonic cleaning for 15 minutes, then rinse with deionized water, finally dehydrate with anhydrous ethanol, blow dry with nitrogen, and dry with an oven lamp for later use.

[0066] 3. Fabricate the metallization layer of aluminum nitride ceramic substrate 1;

[0067] 3.1 Select a magnetron sputtering stage with four target positions and deposit a composite metal layer by sputtering; place the aluminum nitride ceramic substrate 1 in a tray and send it into the sputtering chamber of the magnetron sputtering stage, and heat the substrate to a temperature of 170°C;

[0068] 3.2 Then, the aluminum nitride ceramic substrate 1 is subjected to reverse sputtering. The aluminum nitride ceramic substrate 1 is bombarded at a power of 160W for 310s to remove the contamination layer on the substrate surface, activate the substrate surface, and improve the adhesion of the sputtered film layer on the substrate surface.

[0069] 3.3. A CrSi-NiCr-Au composite film is sputtered onto the surface of the aluminum nitride ceramic substrate 1. First, a CrSi layer is sputtered at a power of 110W for 510s with an argon flow rate of 15sccm. During sputtering, the high-pressure valve is first shut off to partially close the vacuum channel, and then the oxygen flow meter is turned on to introduce a certain amount of oxygen for reactive sputtering at a flow rate of 4sccm. The oxygen combines with the incident deposited atoms to form an oxide intermediate layer, which enhances the adhesion of the film. Immediately after sputtering the CrSi layer, a NiCr film is sputtered at a power of 310W for 310s. Finally, an Au layer is sputtered at a power of 210W for 310s. After sputtering, the aluminum nitride ceramic substrate 1 is removed, and the other side is sputtered using the same method to form a CrSi-NiCr-Au composite metallization layer 2 on both sides of the substrate. Figure 1 As shown.

[0070] 4. Cut the aluminum nitride ceramic substrate 1 after the metallization layer 2 has been deposited into the size of the temperature sensing chip 3 to be packaged. Then place the metal shell 5 on the sintering mold, place the gold-tin solder sheet 4 on the metal shell 5, place the cut aluminum nitride ceramic substrate 1 on the gold-tin solder sheet 4, place the gold-tin solder sheet 4 on the aluminum nitride ceramic substrate 1 again, and finally place the chip 3. Then put them together in the eutectic bonding furnace for sintering.

[0071] 5. Use a programmable vacuum eutectic bonding furnace for eutectic sintering. After welding, wait for the temperature to drop below 70℃, open the chamber door, and remove the eutecticized components. Figure 2 and Figure 3 As shown. Under a 30-60x microscope, the solder of the product with good eutectic bonding is well wetted, and there are no holes around the chip 3. The eutectic sintering of the temperature sensing chip 3, the aluminum nitride ceramic metallization substrate, and the shell 5 can then be completed, thus completing the temperature sensor chip packaging process.

[0072] The steps for eutectic sintering are as follows:

[0073] (1) First, evacuate the vacuum chamber and fill it with nitrogen for more than 80 seconds each time. Repeat this cycle twice to purify the atmosphere inside the vacuum chamber. Then, start heating to bring the furnace temperature to 190°C. At this time, formic acid is introduced and the flow rate is controlled at the maximum value of 10 s lm. The formic acid decomposes upon heating to produce hydrogen. The hydrogen neutralizes the oxygen in the vacuum chamber and provides the reducing gas required for welding - hydrogen. The mold and the shell 5 are preheated.

[0074] (2) Continue to heat up to 290℃ and hold the temperature for 200s to fully preheat the mold and tube shell 5 in preparation for the melting of the solder eutectic.

[0075] (3) After the constant temperature is completed, the temperature is rapidly increased to 360°C within 110s, and then kept constant for 40s to melt the gold-tin solder sheet 4, thus ending the eutectic process.

[0076] (4) Turn off the formic acid flow, evacuate the vacuum chamber and remove the remaining formic acid; then turn off the heating and fill with nitrogen to cool down.

[0077] 6. Finally, the product after eutectic sintering is bonded with gold wire ball bonding machine, and then sealed with energy storage welding machine to complete the packaging of temperature sensor chip.

[0078] To test the bonding strength between the aluminum nitride ceramic substrate and the metal casing after eutectic sintering, 10 eutectic sintered products were selected from the above embodiments for shear force testing. Due to the high bonding strength of the gold-tin solder, a non-destructive shear strength test was performed, and the test data were completely satisfactory. The test data are shown in Table 1.

[0079]

[0080]

[0081] Table 1

[0082] As can be seen from Table 1, the temperature sensor chip packaged according to the embodiments of the present invention fully complies with the standard requirements of GJB548C-2021 "Test Methods and Procedures for Microelectronic Devices".

[0083] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A packaging process for a temperature sensor chip, characterized in that: Includes the following steps: (1) Select an aluminum nitride ceramic substrate and choose the corresponding size of gold-tin solder sheet according to the size of the chip; (2) Cleaning of aluminum nitride ceramic substrate; (3) Fabrication of the metallization layer on the aluminum nitride ceramic substrate; 3.1 Select a magnetron sputtering stage with four target positions and deposit a composite metal layer by sputtering; place the aluminum nitride ceramic substrate in a tray and send it into the sputtering chamber of the magnetron sputtering stage, and heat the substrate to a temperature of 160℃±10℃. 3.2 Then, the aluminum nitride ceramic substrate is subjected to reverse sputtering. The aluminum nitride ceramic substrate is bombarded at a power of 150W±10W for 300s±10s to remove the contamination layer on the substrate surface, activate the substrate surface, and improve the adhesion of the sputtered film layer on the substrate surface. 3.

3. Sputtering a CrSi-NiCr-Au composite film on the substrate surface: First, sputter the CrSi layer at a power of 100W±10W for 500s±10s with an argon flow rate of 13sccm±2sccm. During sputtering, the high-pressure valve was shut off to partially close the vacuum channel, and then the oxygen flow meter was turned on to introduce a certain amount of oxygen for reaction sputtering at a flow rate of 3sccm±1sccm. Immediately after sputtering the CrSi layer, the NiCr film was sputtered at a power of 300W±10W for 300s±10s. Finally, the Au layer was sputtered at a power of 200W±10W for 300s±10s. After sputtering, the aluminum nitride ceramic substrate was removed, and the other side was sputtered and deposited in the same way, so that CrSi-NiCr-Au composite metallization layer was formed on both sides of the substrate; (4) Cut the aluminum nitride ceramic substrate after the metallization layer has been deposited into pieces according to the size of the chip. Then place the metal shell on the sintering mold, place the gold-tin solder sheet on the metal shell, place the cut aluminum nitride ceramic substrate on the gold-tin solder sheet, place the gold-tin solder sheet on the aluminum nitride ceramic substrate again, and finally place the chip; and put them together in the eutectic bonding furnace for sintering. (5) Use a programmable vacuum eutectic welding furnace for eutectic sintering. After welding, wait for the temperature to drop below 70°C, open the chamber door and take out the device. (6) Finally, the product after eutectic sintering is bonded and capped to complete the encapsulation.

2. The packaging process for a temperature sensor chip according to claim 1, characterized in that: The aluminum nitride ceramic substrate has a thickness of 0.3±0.02mm and a thermal conductivity of ≥170W / m·k.

3. The packaging process for a temperature sensor chip according to claim 1, characterized in that: When cleaning the aluminum nitride ceramic substrate, it is first ultrasonically cleaned with acetone for 15 minutes, then rinsed with deionized water, and finally dehydrated with anhydrous ethanol, dried with nitrogen, and then dried with an oven lamp for later use.

4. The packaging process for a temperature sensor chip according to claim 1, characterized in that: The steps for eutectic sintering are as follows: (1) First, evacuate the vacuum chamber and fill it with nitrogen to purify the atmosphere inside the vacuum chamber; then start heating to make the temperature inside the furnace reach 180℃±10℃. At this time, formic acid is introduced and the flow rate is controlled at the maximum value of 8slm~10slm. The formic acid decomposes when heated to produce hydrogen. The hydrogen neutralizes the oxygen in the vacuum chamber and provides the reducing gas required for welding. The mold and the shell are preheated. (2) Continue to heat up to 280℃±10℃ and hold the temperature for 200s~300s to fully preheat the mold and the shell, in preparation for the melting of the solder eutectic. (3) After the constant temperature is completed, the temperature is rapidly increased to 350℃±10℃ within 100s±10s, and the temperature is kept constant for 50s±10s to melt the gold-tin solder sheet and end the eutectic process. (4) Turn off the formic acid flow, evacuate the vacuum chamber and remove the remaining formic acid; then turn off the heating and fill with nitrogen to cool down.

Images