High-purity low-radioactivity spherical silicon micropowder and preparation method thereof

Abstract

The invention discloses high-purity low-radioactivity spherical silicon micropowder. In the silicon micropowder, the content of SiO2 is not lower than 99.90 percent, the content of radioelement U is less than or equal to 1*10g / g, sphericization ratio is between 90 and 100 percent, and non-crystalline ratio is between 99 and 100 percent. The method for preparing the silicon micropowder comprises the following steps: preparing stable silica sol which has purity not lower than 99.90 percent and the ion content of an arbitrary impurity less than or equal to 5*10g / g by a silicon source with the content of radioelement U being less than or equal to 1*10g / g; concentrating the silica sol to lead the solid content of the silica sol to be between 41 and 70 percent; granulating the concentrated silica sol to lead grain diameter of the silica sol to be between 0.5 and 60 mu meters; roasting the granulated silicon oxide micropowder at a temperature of between 500 and 1,100 DEG C; and carrying out sphericization treatment on the micropowder in a flame burner and a sphericizing furnace, and classifying and collecting the micropowder after cooling to obtain the high-purity low-radioactivity spherical silicon micropowder. The spherical silicon micropowder of the invention can meet the requirement of a large-scale integrated circuit on capsulation packing, and the invention has simple process, low cost, simple required equipment, and is applicable to industrial production.

Description

technical field

[0001] The invention relates to a high-purity, low-radioactive spherical silicon micropowder used in large-scale integrated circuit packaging and a preparation method thereof. Background technique

[0002] Spherical silica powder is widely used in the packaging of semiconductor integrated circuits. With the development of large-scale and ultra-large-scale integrated circuits, the requirements for packaging fillers are getting higher and higher. Not only high purity, ultra-fine, spherical, but also radioactive elements are required. Low content. The α-rays emitted by the radioactive elements in the packaging material make the integrated circuit not work properly, produce soft errors, and destroy the information stored in the integrated circuit. When packaging more than 16M memories, the problem of soft errors caused by α-rays will become very prominent. Therefore, VLSI puts forward stricter requirements on the content of radioactive elements in spherical sil...

Examples

Embodiment 1

[0030] With the content of radioactive element U≤1×10 -9 The silicon source of g / g is raw material preparation silica sol, and the purity of silica sol is 99.98% (wherein any kind of impurity ion content all≤5×10 -6 g / g), the solid content of the silica sol after concentration is 41%, and the particle size is 4.5 μm through air-flow spray granulation, roasting at 800 °C for 1 h, liquefied petroleum gas (LPG) is the fuel gas, oxygen is the combustion gas, and oxygen is the delivery gas. Powder carrier gas, adjust the pressure and flow rate of oxygen and LPG, then ignite, preheat the spheroidizing furnace for 50 minutes (generally, the preheating temperature should not be lower than 1500°C), and the powder feeding rate is 300g / min. Analysis of SiO in products by gravimetric method 2 content, ICP-MS detection of radioactive element content, laser particle size analyzer to test particle size and SEM of the product (the SEM image of the product is shown in figure 1 Shown) and XRD...

Embodiment 2

[0032] With the content of radioactive element U≤1×10 -9 The silicon source of g / g is raw material preparation silica sol, and the purity of silica sol is 99.98% (wherein any kind of impurity ion content all≤5×10 -6 g / g), the solid content is 50% after the silica sol is concentrated, the particle size after granulation is 15.4 μm, roasting 1h at 800°C, acetylene is the fuel gas, oxygen is the combustion gas, and oxygen is the carrier gas for powder delivery. , the pressure and flow rate of acetylene and then ignite, the spheroidizing furnace is preheated for 50 minutes, and the powder feeding rate is 100g / min. Analyzed by the same method as Example 1, prepared SiO 2 The content is 99.96%, and the radioactive element U content is 0.05×10 -9 Spherical silica powder with g / g, median particle size of 9.6μm, spheroidization rate of 92%, and amorphous rate of 100%.

Embodiment 3

[0034] With the content of radioactive element U≤1×10 -9 The silicon source of g / g is raw material preparation silica sol, and the purity of silica sol is 99.99% (wherein any impurity ion content all≤5×10 -6 g / g), the solid content of the silica sol after concentration is 60%, the particle size after granulation is 40.6 μm, roasting 40min at 1100°C, natural gas is the fuel gas, oxygen is the combustion gas, and oxygen is the carrier gas for powder delivery. After the pressure and flow of natural gas are ignited, the spheroidizing furnace is preheated for 50 minutes, and the powder feeding rate is 50 g / min. Analyzed by the same method as Example 1, prepared SiO 2 The content is 99.96%, and the radioactive element U content is 0.01×10 -9 Spherical silica powder with g / g, medium particle size of 22.6μm, spheroidization rate of 99%, and amorphous rate of 99%.

technical field

[0001] The invention relates to a high-purity, low-radioactive spherical silicon micropowder used in large-scale integrated circuit packaging and a preparation method thereof. Background technique

[0002] Spherical silica powder is widely used in the packaging of semiconductor integrated circuits. With the development of large-scale and ultra-large-scale integrated circuits, the requirements for packaging fillers are getting higher and higher. Not only high purity, ultra-fine, spherical, but also radioactive elements are required. Low content. The α-rays emitted by the radioactive elements in the packaging material make the integrated circuit not work properly, produce soft errors, and destroy the information stored in the integrated circuit. When packaging more than 16M memories, the problem of soft errors caused by α-rays will become very prominent. Therefore, VLSI puts forward stricter requirements on the content of radioactive elements in spherical sil...

Examples

Embodiment 1

[0030] With the content of radioactive element U≤1×10 -9 The silicon source of g / g is raw material preparation silica sol, and the purity of silica sol is 99.98% (wherein any kind of impurity ion content all≤5×10 -6 g / g), the solid content of the silica sol after concentration is 41%, and the particle size is 4.5 μm through air-flow spray granulation, roasting at 800 °C for 1 h, liquefied petroleum gas (LPG) is the fuel gas, oxygen is the combustion gas, and oxygen is the delivery gas. Powder carrier gas, adjust the pressure and flow rate of oxygen and LPG, then ignite, preheat the spheroidizing furnace for 50 minutes (generally, the preheating temperature should not be lower than 1500°C), and the powder feeding rate is 300g / min. Analysis of SiO in products by gravimetric method 2 content, ICP-MS detection of radioactive element content, laser particle size analyzer to test particle size and SEM of the product (the SEM image of the product is shown in figure 1 Shown) and XRD...

Embodiment 2

[0032] With the content of radioactive element U≤1×10 -9 The silicon source of g / g is raw material preparation silica sol, and the purity of silica sol is 99.98% (wherein any kind of impurity ion content all≤5×10 -6 g / g), the solid content is 50% after the silica sol is concentrated, the particle size after granulation is 15.4 μm, roasting 1h at 800°C, acetylene is the fuel gas, oxygen is the combustion gas, and oxygen is the carrier gas for powder delivery. , the pressure and flow rate of acetylene and then ignite, the spheroidizing furnace is preheated for 50 minutes, and the powder feeding rate is 100g / min. Analyzed by the same method as Example 1, prepared SiO 2 The content is 99.96%, and the radioactive element U content is 0.05×10 -9 Spherical silica powder with g / g, median particle size of 9.6μm, spheroidization rate of 92%, and amorphous rate of 100%.

Embodiment 3

[0034] With the content of radioactive element U≤1×10 -9 The silicon source of g / g is raw material preparation silica sol, and the purity of silica sol is 99.99% (wherein any impurity ion content all≤5×10 -6 g / g), the solid content of the silica sol after concentration is 60%, the particle size after granulation is 40.6 μm, roasting 40min at 1100°C, natural gas is the fuel gas, oxygen is the combustion gas, and oxygen is the carrier gas for powder delivery. After the pressure and flow of natural gas are ignited, the spheroidizing furnace is preheated for 50 minutes, and the powder feeding rate is 50 g / min. Analyzed by the same method as Example 1, prepared SiO 2 The content is 99.96%, and the radioactive element U content is 0.01×10 -9 Spherical silica powder with g / g, medium particle size of 22.6μm, spheroidization rate of 99%, and amorphous rate of 99%.

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