A negative thermal expansion electronic packaging material Cu2V2O7 prepared by ultrasonic spray pyrolysis and its preparation method

Abstract

The present invention discloses a negative thermal expansion electronic packaging material Cu2V2O7 prepared by ultrasonic spray pyrolysis and a preparation method thereof. Using deionized water as a solvent, a copper ion solution A and a vanadium ion solution B are prepared. The solution A and the solution B are mixed to obtain a precursor solution; the precursor solution is subjected to ultrasonic spray treatment to obtain misty droplets; pyrolysis and drying are carried out, and the product is collected and calcined at 670 °C to 700 °C for 2 h to obtain Cu2V2O7 nano-spherical particles. The negative thermal expansion material Cu2V2O7 prepared by the ultrasonic spray pyrolysis method is spherical and near-spherical, has high fluidity, and is suitable for practical applications. The preparation method of the present invention has low cost, simple process, low requirements for equipment, and is easy to industrialize production.

Description

Technical Field

[0001] The present invention belongs to the technical field of preparation of electronic packaging materials, and relates to a preparation method of a negative thermal expansion material for integrated circuit packaging, and particularly to a negative thermal expansion electronic packaging material Cu2V2O7 prepared by ultrasonic spray pyrolysis and a preparation method thereof. Background Art

[0002] In electronic packaging, the main requirements for integrated circuit packaging are high moisture resistance, low stress, low α-ray, resistance to impregnation and reflow soldering after packaging, and good plastic packaging process performance. For these requirements, inorganic fillers must be doped in the resin matrix of the epoxy plastic packaging material.

[0003] Spherical inorganic fillers have many advantages. First, according to the filling process of the packaging material, after the filler is mixed with epoxy resin, it is injected into the gap between the flip chip and the substrate, and the gap is filled by the action of capillary force. The surface of the sphere has good fluidity, the spherical filler is evenly mixed with the resin by stirring, the resin addition amount is small, and the filling amount of the powder can reach the highest. Therefore, spheroidization means an increase in the filling rate of the filler. The higher the filling rate, the smaller its thermal expansion coefficient and the higher its thermal conductivity, and the better the performance of the electronic components produced therefrom. Second, the stress concentration of the plastic packaging material formed by spheroidization is the smallest and the strength is the highest. When the stress concentration of the plastic packaging material of diamond powder is 1, the stress of the spherical powder is only 0.6. Therefore, when the spherical powder plastic packaging material is used to package integrated circuit chips, the yield is high, and mechanical damage is not easily generated during transportation, installation and use. Finally, the spherical powder has a small friction coefficient and little wear on the mold. Compared with diamond powder, the service life of the mold can be doubled, the packaging cost can be reduced, and the economic benefit can be improved.

[0004] Currently, the filler mainly used is spherical silica powder, but its preparation process is complex, the price is expensive, the energy consumption is high (2500 °C), the carbon emission is large, the high-end products are monopolized by the United States and Japan, and the thermal conductivity is low (10 W / m·k), and its intrinsic property shows positive expansion. Since the thermal expansion coefficient of the packaging material is The thermal expansion coefficient of the chip is The thermal expansion coefficient of the packaging substrate is The thermal expansion coefficients between various parts are seriously mismatched. When spherical silica powder is mixed with epoxy resin to form an epoxy plastic packaging material and fills the gap between the chip and the substrate, the problem of thermal expansion mismatch cannot be solved, and mechanical deformations such as delamination, cracking and warping of the integrated circuit are likely to occur during subsequent use.

[0005] To alleviate the thermal expansion mismatch, currently, Mitsui Metal and Misario abroad have developed a new type of negative thermal expansion material to replace spherical silica powder, reducing the thermal expansion coefficient of epoxy molding compounds, but the filler morphology is unknown. There is no preparation of nano-spherical negative thermal expansion materials for the field of electronic packaging at home and abroad. How to design and synthesize a material with a small particle size, spherical morphology, and a thermal expansion coefficient matching that of the resin has become an urgent problem to be solved. Summary of the Invention

[0006] To overcome the deficiencies of the prior art, the purpose of the present invention is to provide a method for preparing a negative thermal expansion electronic packaging material Cu2V2O7 by ultrasonic spray pyrolysis with a simple synthesis route, low cost, and easy industrial production, and to solve the problem of thermal expansion mismatch caused by the mixing of packaging materials and epoxy resin.

[0007] To achieve the above purpose, the present application adopts the following technical solutions to be realized:

[0008] A method for preparing a negative thermal expansion electronic packaging material Cu2V2O7 by ultrasonic spray pyrolysis, comprising the following steps:

[0009] Step 1: Prepare a copper ion solution A with deionized water as the solvent, and the copper ion concentration in the copper ion solution A is 0.08 - 0.09 mol / L;

[0010] Step 2: Prepare a vanadium ion solution B with deionized water as the solvent, and the vanadium ion concentration in the vanadium ion solution B is 0.08 - 0.09 mol / L;

[0011] Step 3: Mix the solution A prepared in Step 1 with the solution B prepared in Step 2, stir, and adjust the pH value of the mixed solution to 1 - 2 to obtain a precursor solution;

[0012] Step 4: Add the precursor solution obtained in Step 3 to an ultrasonic atomizer for ultrasonic spray treatment to obtain misty droplets;

[0013] Step 5: Use an inert gas to send the misty droplets described in Step 4 into a preheated tubular furnace for pyrolysis at 670°C - 700°C, and collect the sample with deionized water on the other side of the tubular furnace, dry, and collect the product;

[0014] Step 6: Calcinate the product described in Step 5 at 670°C - 700°C to obtain Cu2V2O7 nano-spherical particles.

[0015] Furthermore, the copper ion solution A in Step 1 is prepared with Cu(CH3COO)2·H2O, and the vanadium ion solution B in Step 2 is prepared with NH4VO3.

[0016] Further, in the first step, the copper ion solution A is prepared with Cu(NO3)2·3H2O, and in the second step, the vanadium ion solution B is prepared with NH4VO3.

[0017] Further, in the first step, the copper ion solution A is prepared with CuSO4·5H2O, and in the second step, the vanadium ion solution B is prepared with NH4VO3.

[0018] Further, in the third step, the pH value of the mixed solution is adjusted by adding HNO3.

[0019] Further, in the fourth step, the atomization rate of the ultrasonic spray treatment is 280 - 300 mL / h.

[0020] Further, in the fourth step, the ultrasonic frequency of the ultrasonic spray treatment is 1.7 - 2.4 MHz.

[0021] Further, in the fifth step, the flow rate of the inert gas is 1.0 - 1.2 L / min.

[0022] The particle size of the Cu2V2O7 nano-spherical particles is 0.1 - 5 μm.

[0023] The beneficial effects of the present invention are as follows:

[0024] For the negative thermal expansion electronic packaging material Cu2V2O7 prepared by ultrasonic spray pyrolysis in the present invention, from room temperature to 470 K, due to the lateral thermal vibration of the bridging oxygen atoms causing the coupling rotation of the rigid unit modes, the linear thermal expansion coefficient is From 470 K to 610 K, due to the 2+ d 9 Jahn-teller effect of Cu and a small number of micropores, the linear thermal expansion coefficient is From 610 K to 720 K, the linear thermal expansion coefficient is For β-Cu2V2O7 from room temperature to 673 K, due to the lateral vibration of the bridging oxygen atoms shared by the [VO4] tetrahedrons, the stretching effect of the tetrahedrons, and the structural change caused by the oxygen content deficiency due to temperature change resulting in local collapse, the linear thermal expansion coefficient is

[0025] Due to the limited amount of the product prepared in this patent, to verify that Cu2V2O7 can indeed reduce the thermal expansion of epoxy resin, α-Cu2V2O7 was synthesized by the solid-phase method, mixed and cured with epoxy resin in different mass fractions to form a mold, and its thermal expansion coefficient was tested. The thermal expansion coefficient of pure epoxy resin is While the thermal expansion coefficient of the epoxy resin composite added with 20% mass fraction of α-Cu2V2O7 is The coefficient of thermal expansion of the epoxy resin composite with 40% mass fraction of α-Cu2V2O7 added is The coefficient of thermal expansion of the epoxy resin composite with 60% mass fraction of α-Cu2V2O7 added is It can be seen that α-Cu2V2O7 significantly reduces the large thermal expansion of the epoxy resin.

[0026] The copper ion solution A is prepared from Cu(CH3COO)2·H2O, Cu(NO3)2·3H2O or CuSO4·5H2O, and the vanadium ion solution B is prepared from NH4VO3. During the preparation process, 2NH4VO3 + H2O → V2O7 4- + 2NH4 + + 2H + , the copper ion solution A decomposes into the cation Cu 2+ and the anions (CH3COO) - , (NO3) - , (SO4) 2- . During the pyrolysis process, the anions of the copper ion solution A are heated to become gases such as NH3, CO x , NO x , SO x and are discharged. The prepared product has no other element doping and is pure.

[0027] The negative thermal expansion material Cu2V2O7 prepared by the ultrasonic spray pyrolysis method is spherical and near-spherical, has high fluidity, and is suitable for practical applications. The preparation method of the present invention has low cost, simple process, low requirements for equipment, and is easy for industrial production. Brief Description of the Drawings

[0028] Figure 1 The process flow chart of the ultrasonic spray pyrolysis of the present invention;

[0029] Figure 2 The XRD pattern of the sample prepared in Example 1;

[0030] Figure 3 The SEM photograph of the sample prepared in Example 1;

[0031] Figure 4 The XRD pattern of the sample prepared in Example 2;

[0032] Figure 5 The SEM photograph of the sample prepared in Example 2;

[0033] Figure 6 The test data graph of α-Cu2V2O7 reducing the thermal expansion of epoxy resin. Detailed Embodiments

[0034] The technical solutions in the embodiments of the present invention will be described clearly and completely below.

[0035] Example 1

[0036] As Figure 1 , the method for preparing the negative thermal expansion electronic packaging material Cu2V2O7 by ultrasonic spray pyrolysis in this embodiment includes the following steps:

[0037] Step 1: Using Cu(CH3COO)2·H2O as the solute and deionized water as the solvent, prepare solution A; the concentration of solution A is 0.08 mol / L;

[0038] Step 2: Using NH4VO3 as the solute and deionized water as the solvent, prepare solution B; the concentration of solution B is 0.08 mol / L;

[0039] Step 3: Mix the solution A in Step 1 with the solution B in Step 2, stir, add 5 ml of HNO3 to make the pH value = 1, and obtain a precursor solution;

[0040] Step 4: Add the precursor solution in Step 3 to an ultrasonic atomizer with an ultrasonic frequency of 1.7 MHz and an atomization rate of 300 mL / h for ultrasonic spray treatment to obtain misty droplets;

[0041] Step 5: Use an inert gas with a flow rate of 1.2 L / min to send the misty droplets in Step 4 into a preheated tubular furnace at 670 °C for pyrolysis;

[0042] Step 6: On one side of the tubular furnace in Step 5, collect the product with deionized water, dry it, and obtain Cu3V2O7(OH)2·2H2O.

[0043] Step 7: Heat the Cu3V2O7(OH)2·2H2O in Step 6 at a heating rate of 5 °C / min and calcine it at 670 °C for 2 h to obtain α-Cu2V2O7 nanoparticles.

[0044] The XRD of the α-Cu2V2O7 nanoparticles prepared in this embodiment is as Figure 2 shown. It can be seen from Figure 2 that the α-Cu2V2O7 prepared in this embodiment is successfully synthesized.

[0045] The SEM of the α-Cu2V2O7 nanoparticles prepared in this embodiment is as Figure 3 shown. It can be seen from Figure 3 that the morphology of the α-Cu2V2O7 prepared in this embodiment is connected spheres with a smooth surface, and its particle size is in the range of 1 μm to 5 μm.

[0046] Example 2

[0047] The method for preparing the negative thermal expansion electronic packaging material Cu2V2O7 by ultrasonic spray pyrolysis in this embodiment includes the following steps:

[0048] Step 1: Using Cu(NO3)2·3H2O as the solute and deionized water as the solvent, prepare solution A; the concentration of solution A is 0.08 mol / L;

[0049] Step 2: Using NH4VO3 as the solute and deionized water as the solvent, prepare solution B; the concentration of solution B is 0.08 mol / L;

[0050] Step 3: Mix the solution A described in Step 1 with the solution B described in Step 2, stir, add 5 ml of HNO3 to make the pH value = 1, and obtain a precursor solution;

[0051] Step 4: Add the precursor solution described in Step 3 to an ultrasonic nebulizer with an ultrasonic frequency of 1.9 MHz and an atomization rate of 300 mL / h for ultrasonic spray treatment to obtain misty droplets;

[0052] Step 5: Use an inert gas with a flow rate of 1.2 L / min to send the misty droplets described in Step 4 into a preheated tubular furnace at 680 °C for pyrolysis;

[0053] Step 6: After cooling the tubular furnace described in Step 5 to room temperature, scrape the product on the inner wall to obtain β-Cu2V2O7 nanoparticles.

[0054] The XRD of the β-Cu2V2O7 nanoparticles prepared in this embodiment is as Figure 4 shown, and it can be seen from Figure 4 that the β-Cu2V2O7 prepared in this embodiment is successfully synthesized.

[0055] The SEM of the β-Cu2V2O7 nanoparticles prepared in this embodiment is as Figure 5 shown, and it can be seen from Figure 5 that the β-Cu2V2O7 particles prepared in this embodiment are spherical, and their particle size is in the range of 0.1 μm to 0.5 μm. The sphericity represents the degree of closeness of the particles to a spherical shape, and is calculated by dividing the radius of the largest inscribed circle of the particle SEM image by the radius of the smallest circumscribed circle. Using IPP software, calculate the sphericity of the particles prepared in Example 2, and its average sphericity is 93.04%.

[0056] Example 3

[0057] The method for preparing the negative thermal expansion electronic packaging material Cu2V2O7 by ultrasonic spray pyrolysis in this embodiment includes the following steps:

[0058] Step 1: Prepare solution A with Cu(NO3)2·3H2O as the solute and deionized water as the solvent; the concentration of solution A is 0.09 mol / L;

[0059] Step 2: Prepare solution B with NH4VO3 as the solute and deionized water as the solvent; the concentration of solution B is 0.085 mol / L;

[0060] Step 3: Mix the solution A described in Step 1 with the solution B described in Step 2, stir, and add HNO3 to make the pH value = 2 to obtain a precursor solution;

[0061] Step 4: Add the precursor solution described in Step 3 to an ultrasonic nebulizer with an ultrasonic frequency of 2.4 MHz and an atomization rate of 280 mL / h for ultrasonic spray treatment to obtain misty droplets;

[0062] Step 5: Use an inert gas with a flow rate of 1.2 L / min to send the misty droplets described in Step 4 into a preheated tubular furnace at 700 °C for pyrolysis;

[0063] Step 6: After the tubular furnace described in Step 5 cools down to room temperature, scrape the product on the inner wall to obtain β-Cu2V2O7 nanoparticles.

[0064] Example 4

[0065] As Figure 1 , the method for preparing the negative thermal expansion electronic packaging material Cu2V2O7 by ultrasonic spray pyrolysis in this example includes the following steps:

[0066] Step 1: Prepare solution A with Cu(CH3COO)2·H2O as the solute and deionized water as the solvent; the concentration of solution A is 0.085 mol / L;

[0067] Step 2: Prepare solution B with NH4VO3 as the solute and deionized water as the solvent; the concentration of solution B is 0.09 mol / L;

[0068] Step 3: Mix the solution A described in Step 1 with the solution B described in Step 2, stir, and add HNO3 to make the pH value = 1 to obtain a precursor solution;

[0069] Step 4: Add the precursor solution described in Step 3 to an ultrasonic nebulizer with an ultrasonic frequency of 1.7 MHz and an atomization rate of 300 mL / h for ultrasonic spray treatment to obtain misty droplets;

[0070] Step 5: Use an inert gas with a flow rate of 1.2 L / min to send the misty droplets described in Step 4 into a preheated tubular furnace at 690 °C for pyrolysis;

[0071] Step 6: On one side of the tubular furnace described in Step 5, collect the product with deionized water, and dry it to obtain Cu3V2O7(OH)2·2H2O.

[0072] Step 7: Heat the Cu3V2O7(OH)2·2H2O described in Step 6 at a heating rate of 5 °C / min, and calcine it at 690 °C for 2 h to obtain α-Cu2V2O7 nanoparticles.

[0073] Example 5

[0074] As Figure 1 , the method for preparing the negative thermal expansion electronic packaging material Cu2V2O7 by ultrasonic spray pyrolysis in this example includes the following steps:

[0075] Step 1: Using CuSO4·5H2O as the solute and deionized water as the solvent, prepare solution A; the concentration of solution A is 0.085 mol / L;

[0076] Step 2: Using NH4VO3 as the solute and deionized water as the solvent, prepare solution B; the concentration of solution B is 0.09 mol / L;

[0077] Step 3: Mix the solution A described in Step 1 with the solution B described in Step 2, stir, and add HNO3 to make the pH value = 1 to obtain the precursor solution;

[0078] Step 4: Add the precursor solution described in Step 3 to an ultrasonic nebulizer with an ultrasonic frequency of 1.7 MHz and an atomization rate of 300 mL / h for ultrasonic spray treatment to obtain misty droplets;

[0079] Step 5: Use an inert gas with a flow rate of 1.2 L / min to send the misty droplets described in Step 4 into a preheated 690 °C tubular furnace for pyrolysis;

[0080] Step 6: On one side of the tubular furnace described in Step 5, collect the product with deionized water, and dry it to obtain Cu3V2O7(OH)2·2H2O.

[0081] Step 7: Heat the Cu3V2O7(OH)2·2H2O described in Step 6 at a heating rate of 5 °C / min, and calcine it at 690 °C for 2 h to obtain α-Cu2V2O7 nanoparticles.

Claims

1. A method for preparing a negative thermal expansion electronic packaging material Cu2V2O7 by ultrasonic spray pyrolysis, characterized in that It includes the following steps: Step 1: Prepare copper ion solution A with deionized water as the solvent. The copper ion concentration in the copper ion solution A is 0.08 - 0.09 mol / L. Step 2: Prepare vanadium ion solution B with deionized water as the solvent. The vanadium ion concentration in the vanadium ion solution B is 0.08 - 0.09 mol / L. Step 3: Mix the solution A prepared in Step 1 with the solution B prepared in Step 2, stir, and adjust the pH value of the mixed solution to 1 - 2 by adding HNO3 to obtain a precursor solution. Step 4: Add the precursor solution obtained in Step 3 into an ultrasonic nebulizer for ultrasonic spray treatment to obtain misty droplets. Step 5: Use an inert gas to send the misty droplets described in Step 4 into a preheated tube furnace, and pyrolyze at 670°C - 700°C for 4 - 8 h; collect the sample with deionized water on the other side of the tube furnace, dry, and collect the product. Step 6: Heat the product described in Step 5 at a rate of 5°C / min, and calcine at 670°C - 700°C for 2 h to obtain Cu2V2O7 nano-spherical particles.

2. The method for preparing the negative thermal expansion electronic packaging material Cu2V2O7 by ultrasonic spray pyrolysis according to claim 1, characterized in that: In Step 1, the copper ion solution A is prepared with Cu(CH3COO)2·H2O, and in Step 2, the vanadium ion solution B is prepared with NH4VO3.

3. The method for preparing the negative thermal expansion electronic packaging material Cu2V2O7 by ultrasonic spray pyrolysis according to claim 1, characterized in that: In Step 1, the copper ion solution A is prepared with Cu(NO3)2·3H2O, and in Step 2, the vanadium ion solution B is prepared with NH4VO3.

4. The method for preparing the negative thermal expansion electronic packaging material Cu2V2O7 by ultrasonic spray pyrolysis according to claim 1, wherein: In Step 1, the copper ion solution A is prepared with CuSO4·5H2O, and in Step 2, the vanadium ion solution B is prepared with NH4VO3.

5. The method for preparing negative thermal expansion electronic packaging material Cu2V2O7 by ultrasonic spray pyrolysis according to claim 1, wherein: In Step 4, the atomization rate of the ultrasonic spray treatment is 280 - 300 mL / h.

6. The method for preparing the negative thermal expansion electronic packaging material Cu2V2O7 by ultrasonic spray pyrolysis according to claim 1, wherein: In Step 4, the ultrasonic frequency of the ultrasonic spray treatment is 1.7 - 2.4 MHz.

7. The method for preparing the negative thermal expansion electronic packaging material Cu2V2O7 by ultrasonic spray pyrolysis according to claim 1, wherein: In Step 5, the flow rate of the inert gas is 1.0 - 1.2 L / min.

8. The negative thermal expansion electronic packaging materials prepared by the method according to any one of claims 1 - 7 are all Cu2V2O7, and the particle size of the Cu2V2O7 nano-spherical particles is 0.1 - 5 μm.

9. Application of the negative thermal expansion electronic packaging material Cu2V2O7 described in claim 8 in integrated circuit packaging.

Images