CN100395887C - Integrated circuit packaging structure and manufacturing method thereof - Google Patents

Abstract

The present invention relates to an integrated circuit packaging structure which comprises an integrated circuit chip arranged on a base plate, an integrated radiating fin positioned above the integrated circuit chip and a carbon nanotube array, wherein the lower end of the edge of the integrated radiating fin is fixed to the base plate, and the integrated radiating fin comprises an inner surface and an outer surface; the carbon nanotube array is arranged between the integrated circuit chip and the integrated radiating fin. The carbon nanotube array is formed on the inner surface of the integrated radiating fin, and both ends of the carbon nanotube array respectively vertically contact the integrated radiating fin and the integrated circuit chip; nanometer metal materials with high heat conductivity is filled in carbon nanotubes.

Description

Integrated circuit packaging structure and manufacturing method thereof

【Technical field】

The invention relates to an integrated circuit packaging structure and a manufacturing method thereof, in particular to an integrated circuit packaging structure using a carbon nanotube array for heat conduction and a manufacturing method thereof.

【Background technique】

In the field of packaging of semiconductor integrated circuits, with the continuous improvement and development of semiconductor integrated circuits, their functions continue to increase while their volumes continue to decrease, their density continues to increase, and their packaging sizes continue to decrease. Since the integrated circuit chip performs calculation and processing in such a small space when it is working, it will inevitably generate a considerable amount of heat. The generated heat must be dissipated in an appropriate way to avoid calculation and processing errors due to overheating of the integrated circuit chip, and in severe cases, damage to the hardware circuit will be caused. Therefore, the heat dissipation problem in the package becomes more and more critical.

In the traditional packaging method, due to the low thermal conductivity of the plastic packaging compound, the heat generated by the integrated circuit chip cannot be dissipated in real time, resulting in excessively high chip temperature and reducing the power that the chip can support. In order to solve this problem, as shown in FIG. 1 , the initial method is to bond a heat sink 5 on the substrate 3 , and then use a plastic sealant 7 to plastic seal the chip 2 , gold wire 4 , heat sink 5 , and the like. The heat sink 5 is located above the chip 2 , and its upper surface is exposed to the air for dissipating the heat generated by the chip 2 and preventing the temperature of the chip 2 from being too high. However, the heat generated by the chip 2 needs to be conducted through the plastic encapsulant 7 to reach the heat sink 5 and dissipate the heat energy. However, since the plastic encapsulation body 7 is a poor thermal conductor, its cooling effect is limited.

With the emergence of thermal interface materials and the development of semiconductor packaging technology, people combine thermal interface materials with semiconductor packaging technology to obtain better heat dissipation effects. Referring to FIG. 2 , the thermal interface material 6 is placed between the top surface of the chip 2 and the inner surface of the heat sink 5 . When the integrated circuit is working, the heat generated by the chip 2 can be transferred to the inner surface of the heat sink 5 by the thermal interface material 6 directly in contact with it, absorbed by the heat sink 5, and dissipated by other heat dissipation devices outside the heat sink 5 . However, this semiconductor integrated circuit packaging method using a thermal interface material is restricted by the thermal conductivity of the thermal interface material itself.

In order to improve the performance of thermal interface materials and increase their thermal conductivity, various materials have been extensively tested. Savas Berber and others published an article titled "Unusually High Thermal Conductivity of Carbon Nanotubes" on the American Physical Society in 2000, pointing out that the thermal conductivity of "Z"-shaped (10,10) carbon nanotubes at room temperature can reach 6600W/ mK, for details, please refer to the literature Phys. Rev. Lett (2000), Vol.84, P.4613. Research on how to use carbon nanotubes in thermal interface materials and give full play to their excellent thermal conductivity has become an important direction to improve the performance of thermal interface materials.

US Patent No. 6,407,922 discloses a thermal interface material utilizing carbon nanotubes for heat conduction, which incorporates carbon nanotubes into a silver colloidal matrix and integrates the thermal interface material by injection molding. The two heat conduction surfaces of the thermal interface material have different areas, and the area of the side contacting the heat sink is greater than the area of the side contacting the heat source. The application of the thermal interface material to the semiconductor package can improve its heat dissipation capability. However, the thermal interface material produced by this method has disadvantages. First, the thickness of the thermal interface material produced by injection molding is relatively large. Although the thermal conductivity of the thermal interface material is high, the volume of the thermal interface material increases. It is not compatible with the trend of device miniaturization, and the thermal interface material lacks flexibility; secondly, the carbon nanotubes are not arranged in an orderly manner in the matrix material, and it is difficult to ensure the uniformity of their distribution in the matrix, so The uniformity of heat conduction is also affected, and the advantage of longitudinal heat conduction of carbon nanotubes is not fully utilized, which affects the thermal conductivity of thermal interface materials.

U.S. Patent Application No. 20040005736 published on January 8, 2004 discloses a thermal interface material based on carbon nanotube arrays, and a semiconductor package structure including the thermal interface material, which puts the thermal interface material in the integrated heat dissipation during packaging Between the integrated heat spreader (Integrated Heat Spreader, IHS) and the integrated circuit chip (DIE), or between the integrated circuit chip and the heat sink (Heat Sink). Wherein, the thermal interface material is a carbon nanotube array mixed with a polymer matrix material, and the carbon nanotubes are uniformly distributed and arranged in the polymer matrix material, which can avoid affecting the thermal interface material due to the disordered arrangement of the carbon nanotubes. At the same time, the carbon nanotube array is basically perpendicular to and extends out of the contact surface of the thermal interface material, ensuring that the carbon nanotubes can directly contact the integrated circuit chip or heat dissipation device. However, the semiconductor packaging structure based on this thermal interface material has disadvantages. First, due to the poor thermal conductivity of the polymer matrix material, the thermal interface material formed by mixing carbon nanotubes with the polymer matrix cannot fully utilize the carbon nanotubes. The thermal conductivity of nanotubes, and the thermal interface material will cause uneven heat conduction due to the uneven heating of the chip during application, which will affect the thermal conduction efficiency and stability of the entire thermal interface material, and further affect the packaging structure. second, the thermal interface material that mixes the carbon nanotube array in the polymer matrix in the above-mentioned semiconductor packaging structure is formed on the integrated circuit chip (DIE), because the integrated circuit chip cannot withstand the required heat for forming the carbon nanotube array. Due to the high temperature, it is necessary to form the carbon nanotube array thermal interface material on the substrate in advance, and then fabricate the integrated circuit chip on the substrate. The manufacturing and packaging process is relatively complicated, which is not conducive to popularization and application.

Therefore, it is very necessary to provide an integrated circuit packaging structure that can fully utilize the thermal conductivity of carbon nanotubes, has a good heat dissipation effect, and is easy to manufacture, and a manufacturing method of the packaging structure.

【Content of invention】

In order to solve the technical problems of the prior art, the purpose of the present invention is to provide an integrated circuit packaging structure that can fully utilize the heat conduction performance of carbon nanotubes, has good heat dissipation effect, and is easy to manufacture. .

Another object of the present invention is to provide a method for manufacturing such an integrated circuit package structure.

In order to achieve the purpose of the present invention, the present invention provides an integrated circuit packaging structure, which includes: a substrate; an integrated circuit chip is arranged on the substrate; an integrated heat sink is placed above the integrated circuit chip, and the lower end of its edge is fixed on the substrate , the integrated heat sink includes an inner surface and an outer surface; and a carbon nanotube array is arranged between the above-mentioned integrated circuit chip and the heat dissipation device; wherein, the carbon nanotube array is formed on the inner surface of the integrated heat sink, its The two ends are in vertical contact with the integrated heat sink and the integrated circuit chip respectively.

In the integrated circuit packaging structure of the present invention, the carbon nanotubes are filled with nano metal materials with high thermal conductivity.

The integrated circuit packaging structure may further include a carbon nanotube array formed on the outer surface of the integrated heat sink. When applied, the two ends of the carbon nanotube are in vertical contact with the integrated heat sink and the external heat sink respectively. The carbon nanotube array can also be a carbon nanotube array filled with nano metal materials with high thermal conductivity in the tube.

To achieve another object of the present invention, the present invention also provides a method for manufacturing such an integrated circuit packaging structure, comprising the following steps:

providing a substrate comprising two opposing surfaces;

Provide an integrated circuit chip and bond the chip on a surface of the substrate, and then electrically connect the integrated circuit chip and the circuit on the substrate through gold wires;

providing an integrated heat sink including an inner surface and an opposite outer surface;

Growing carbon nanotube arrays on the inner surface of the integrated heat sink by chemical methods;

Fixing the integrated heat sink on the substrate, so that the carbon nanotube array is located between the integrated heat sink and the integrated circuit chip, and is in direct vertical contact with the integrated circuit chip;

Set the sealing material on the substrate, integrated circuit chip, and integrated heat sink;

Solder balls on the other surface of the substrate opposite to the chip.

Wherein, the growth method of carbon nanotube array in the present invention comprises the following steps:

Polishing the surface of the integrated heat sink where the carbon nanotube array is to be grown;

Depositing a catalyst on the surface of the integrated heat sink;

The carbon source gas is introduced, and the carbon nanotube array is grown on the surface of the integrated heat sink.

In the manufacturing method of the integrated circuit packaging structure of the present invention, the carbon nanotube array further includes a carbon nanotube array filled with nano-metal materials with high thermal conductivity.

The forming method of the carbon nanotube array filled with nano metal material of the present invention comprises the following steps:

A regularly patterned catalyst layer is spread on the surface of the heat sink where the carbon nanotube array needs to be grown;

Using laser evaporation (Laser Ablation) to instantly gasify graphite rods containing metal elements with high-energy lasers;

Under the argon atmosphere of 500 Torr, the vaporized carbon-based metal vapor is transferred to the surface of the heat sink with the catalyst distributed by flowing argon;

After cooling, a carbon nanotube array filled with nano metal material is obtained.

Compared with the prior art, the present invention has the following advantages based on the thermal conductivity of the carbon nanotube array integrated circuit packaging structure: First, the carbon nanotube array is directly grown on the surface of the integrated heat sink before packaging, the method is simple, and it can avoid the growth time. The impact on the integrated circuit chip; second, the carbon nanotube array can be directly in contact with the integrated heat sink and the integrated circuit chip during application, or directly and vertically contact with the external heat sink, forming multiple heat conduction channels, which can play an excellent role. The excellent thermal conductivity of carbon nanotubes; third, carbon nanotubes are filled with nano-metal materials, which can provide uniform heat dissipation when the heat source generates heat unevenly, thus effectively improving the efficiency and stability of heat conduction.

【Description of drawings】

FIG. 1 is a schematic diagram of a semiconductor integrated circuit packaging structure in the prior art.

FIG. 2 is a schematic diagram of a package structure of a semiconductor integrated circuit packaged with a heat sink in the prior art.

FIG. 3 is a schematic diagram of the first embodiment of the integrated circuit packaging structure of the present invention.

Fig. 4 is a partially enlarged schematic diagram of the third diagram.

FIG. 5 is a schematic diagram of a second embodiment of the integrated circuit packaging structure of the present invention.

FIG. 6 is a schematic flow chart of the manufacturing method of the integrated circuit packaging structure of the present invention.

【Detailed ways】

The present invention will be described in detail below in conjunction with the accompanying drawings and specific embodiments.

Referring to Fig. 3 and Fig. 4, the present invention provides a kind of integrated circuit packaging structure 10, and it comprises: a substrate 11; Connection; an integrated heat spreader (Integrated Heat Spreader, IHS) 13 is arranged on the top of the integrated circuit chip 12, and the integrated heat spreader 13 includes an inner surface and an outer surface, and its edge lower end 131 is bonded on the substrate 11, the integrated heat spreader The heat sink plays the role of sealing and protecting the integrated circuit chip 12. At the same time, the lower end 131 of the edge of the integrated heat sink 13 is electrically connected to the ground electrode of the substrate 11 through a circuit, which plays the role of electrostatic shielding; a carbon nanotube array 14 is formed on the integrated circuit. The inner surface of the heat sink 13, the carbon nanotube array 14 includes a plurality of carbon nanotubes 141 that are uniformly distributed and parallel to each other, and the two ends of the carbon nanotubes 141 are in vertical contact with the integrated circuit chip 12 and the integrated heat sink 13 respectively, forming a plurality of carbon nanotubes. a thermal channel. Wherein, the carbon nanotube array 14 is directly grown on the integrated heat sink 13, which is equivalent to a layer of thermal interface material. The height of the carbon nanotube array 14 can be controlled by controlling its growth time, and the height of the carbon nanotube array 14 in the present invention is 0.01-0.1 mm. Preferably, the carbon nanotubes 141 formed in the present invention are all filled with nano-metal materials with high thermal conductivity, which can better improve the efficiency of heat conduction and significantly improve the stability of heat conduction during application. The nano-metal materials of the present invention include nano copper material. In addition, the substrate 11 of the present invention can be electrically connected to the motherboard 17 through the connector 16 , so as to complete the function of connecting with other electronic components on the motherboard 17 .

Please refer to Fig. 5, in order to obtain better heat dissipation effect, in practical application, can further form a carbon nanotube array 15 with the same method on the outer surface of integrated heat sink 13, thereby transfer from integrated circuit chip 12 to The heat on the integrated heat sink 13 is better transferred to the external heat sink 18 and dissipated quickly, thereby effectively reducing the operating temperature of the integrated circuit chip 12 . The external heat sink 18 in this embodiment is selected from finned heat sinks.

Please refer to FIG. 6, the manufacturing method of the integrated circuit packaging structure of the present invention includes the following steps:

Step 100 is providing a substrate comprising two opposite surfaces;

Step 200 is providing an integrated circuit chip and bonding the chip on a surface of the substrate, and then electrically connecting the integrated circuit chip and the circuit on the substrate through gold wires;

Step 300, providing an integrated heat sink, which includes an inner surface and an opposite outer surface, and the material of the heat sink includes metallic copper;

Step 400, grow a carbon nanotube array on the inner surface of the integrated heat sink by chemical method, the thickness of the carbon nanotube array is 0.01-0.1 mm;

Step 500, fixing the integrated heat sink on the substrate, so that the carbon nanotube array is located between the integrated heat sink and the integrated circuit chip, and is in direct vertical contact with the integrated circuit chip, and at the same time, the integrated heat sink is electrically connected to the substrate to To the role of electrostatic shielding;

Step 600, setting the sealing material on the substrate, the integrated circuit chip, and the integrated heat sink, wherein the sealing setting method includes transfer, molding, dispensing and vacuum printing;

In step 700, solder balls on the other surface of the substrate opposite to the chip to connect the connector, and electrically connect with the main board through the connector.

Wherein, the present invention can further grow the carbon nanotube array on the outer surface of the heat sink. When applied, the carbon nanotube array is located between the heat sink and the external heat sink, which is conducive to better heat transfer.

Preferably, the carbon nanotube array formed in the present invention includes a carbon nanotube array filled with a high thermal conductivity nano-metal material, and the nano-metal material in this embodiment is selected from nano-copper materials.

The method for growing a carbon nanotube array on a heat sink of the present invention comprises the following steps:

First, do a chemical mechanical polishing (CMP) on the surface of the heat sink to reduce the surface roughness to 5-10 angstroms, and clean the surface;

Secondly, a catalyst layer is deposited on the surface of the treated heat sink. The thickness of the catalyst layer is 5-30 nanometers. The method of deposition of the catalyst layer can be vacuum thermal evaporation evaporation method or electron beam evaporation method. The material of the catalyst can be iron, cobalt, nickel or their alloys. In this embodiment, iron is selected as the catalyst material, and the thickness of its deposition is 10 nanometers;

Finally, place the heat sink with the catalyst layer in the air and anneal at 300°C to oxidize and shrink the catalyst layer into nanoscale catalyst particles. After the annealing is completed, place the surface of the heat sink with the catalyst particles in the reaction chamber, pass through the carbon source gas acetylene, and use the low-temperature thermal chemical vapor deposition method to grow carbon nanotubes on the catalyst particles to form a carbon nanotube film , The carbon source gas can also choose other carbon-containing gases, such as ethylene. At present, the growth method of carbon nanotube arrays is relatively mature. For details, please refer to the literature Science, 1999, 283, 512-414 and the literature J.Am.Chem.Soc, 2001, 123, 11502-11503. The height of the carbon nanotube array of the present invention is 0.01-0.1 millimeters, and the diameter of the carbon nanotubes grown in this embodiment is 20 nanometers, the height is 50 micrometers, and the spacing is 100 nanometers.

In a preferred mode of the present invention, the method for growing a carbon nanotube array filled with nano-metallic copper material comprises the following steps:

First, do a chemical mechanical polishing (Chemical Mechanical Polish, CMP) on the surface of the heat sink where the carbon nanotube array needs to be grown to reduce the surface roughness to 5-10 angstroms, and spread the surface of the treated heat sink The catalyst layer patterned by the previous rule, the specific method is to firstly spread the photoresist through soft drying, exposure and development according to the predetermined pattern, and then spread the catalyst by vacuum sputtering or volatilization coating method. The material of the catalyst can be iron, cobalt, nickel or their alloys. In this embodiment, iron is selected as the catalyst material, and the thickness of its deposition is 10 nanometers;

Secondly, the graphite rod containing the metal element is vaporized instantly with a high-energy laser by laser evaporation method (Laser Ablation), wherein the high-energy laser is selected from the Nd YAG Laser (Nd YAG Laser), and the metal element selected in this embodiment from metallic copper;

Thirdly, under the argon atmosphere of 500 Torr, the vaporized carbon-based metal vapor is transferred to the surface of the heat sink on which the catalyst has been distributed with flowing argon gas, wherein the content of the metal element is not less than 1%;

Finally, cooling yields carbon nanotube arrays filled with metallic materials.

When the integrated circuit packaging structure of the present invention is applied, since the carbon nanotubes are in direct contact with the heat sink and the integrated circuit chip, further, when the carbon nanotube array is arranged between the heat sink and the external heat sink, the carbon nanotubes It is in direct contact with the heat sink and the external heat sink, so it can give full play to the excellent thermal conductivity of carbon nanotubes, and can well transfer the heat emitted by the integrated circuit chip to the integrated heat sink and quickly dissipate it through the external heat sink. heat radiation. In addition, since the carbon nanotubes are filled with nano-metal materials, the heat conduction efficiency and heat conduction stability can be further improved.

Claims (15)

1. An integrated circuit packaging structure, which comprises a substrate, an integrated circuit chip is arranged on the substrate, an integrated heat sink is placed above the integrated circuit chip, and the lower end of its edge is fixed on the substrate, and the integrated heat sink includes an inner surface And an outer surface, a carbon nanotube array is arranged between the above-mentioned integrated circuit chip and the integrated heat sink, it is characterized in that: the carbon nanotube array is formed on the inner surface of the integrated heat sink, and its two ends are respectively connected with the integrated heat sink and the integrated heat sink Integrated circuit chips are contacted vertically. 2. The integrated circuit packaging structure according to claim 1, characterized in that the carbon nanotubes are further filled with nano-metal materials with high thermal conductivity. 3. The integrated circuit packaging structure according to claim 1, further comprising a carbon nanotube array formed on the outer surface of the integrated heat sink, and the two ends of the carbon nanotubes are in vertical contact with the integrated heat sink and the external heat sink respectively . 4. The integrated circuit packaging structure as claimed in claim 1, wherein the carbon nanotube array has a height of 0.01-0.1 mm. 5. The integrated circuit packaging structure according to claim 2, characterized in that the nano-metal material with high thermal conductivity comprises nano-metal copper material. 6. A method for manufacturing an integrated circuit packaging structure, comprising the following steps: providing a substrate comprising a first surface and a second surface opposite to the first surface; providing an integrated circuit chip and bonding the chip on the first surface of the substrate, and then electrically connecting the integrated circuit chip and the circuit on the substrate through gold wires; providing an integrated heat sink including an inner surface and an opposite outer surface; Growing carbon nanotube arrays on the inner surface of the integrated heat sink by chemical methods; Fixing the integrated heat sink on the substrate, so that the carbon nanotube array is located between the integrated heat sink and the integrated circuit chip, and is in direct vertical contact with the integrated circuit chip; Set the sealing material on the substrate, integrated circuit chip, and integrated heat sink; solder balls on the second surface of the substrate. 7. The manufacturing method of an integrated circuit packaging structure according to claim 6, characterized in that the carbon nanotubes are further filled with nano-metal materials with high thermal conductivity. 8. The method for manufacturing an integrated circuit package structure as claimed in claim 7, further comprising forming a carbon nanotube array also filled with nano-metal material on the outer surface of the integrated heat sink. 9. The method for manufacturing an integrated circuit packaging structure as claimed in claim 6, wherein the method for growing the carbon nanotube array comprises the following steps: Polishing the surface of the integrated heat sink where the carbon nanotube array is to be grown; Depositing a catalyst on the surface of the integrated heat sink; The carbon source gas is introduced, and the carbon nanotube array is grown on the surface of the integrated heat sink. 10. The method for manufacturing an integrated circuit packaging structure as claimed in claim 7, characterized in that the method for forming the carbon nanotube array filled with nano-metal material comprises the following steps: Polishing the surface of the integrated heat sink where the carbon nanotube array is to be grown; A regularly patterned catalyst layer is spread on the surface of the treated heat sink; The graphite rod containing metal elements is vaporized instantly with high-energy laser by laser evaporation method; Under the argon atmosphere of 500 Torr, the vaporized carbon-based metal vapor is transferred to the surface of the heat sink with the catalyst distributed by flowing argon; After cooling, a carbon nanotube array filled with nano metal material is obtained. 11. The method for manufacturing an integrated circuit packaging structure as claimed in claim 10, wherein the method for forming the patterned catalyst layer comprises first following a predetermined pattern on the surface of the integrated heat sink through soft drying, exposure, and developing cloth glazing. Resist, and then vacuum sputtering or volatile coating method on the catalyst. 12. The method for manufacturing an integrated circuit packaging structure as claimed in claim 10, wherein the nano-metal material comprises nano-metal copper material. 13. The method for manufacturing an integrated circuit packaging structure as claimed in claim 10, wherein the content of the metal element in the carbon-based metal vapor is not less than 1%. 14. The manufacturing method of an integrated circuit packaging structure as claimed in claim 10, wherein the high-energy laser is selected from Nd-doped YAG laser. 15. The method for manufacturing an integrated circuit packaging structure as claimed in claim 10, wherein the carbon nanotube array has a height of 0.01-0.1 mm.

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