CN103094125A - Integrated method of carbon nano tube heat dissipation structure and electronic device - Google Patents

Abstract

The invention relates to an integration method of a carbon nanotube heat dissipation structure and an electronic device, which belongs to the technical field of microelectronic technology. The invention provides a simple and efficient integration method of the carbon nanotube heat dissipation structure and electronic devices. The method uses the carbon nanotube array as a heat dissipation structure, deposits a metal wetting layer and makes a solder layer on the free end of the carbon nanotube array, and then peels the carbon nanotubes from the growth substrate to form a heat dissipation structure; The solder layer and the metal wetting layer on the electronic device are heated and welded in contact to realize the integration of the carbon nanotube heat dissipation structure and the electronic device. The invention can directly integrate a carbon nanotube heat dissipation structure with good performance on an electronic device, and overcomes the technical problems of complicated process and low efficiency in other integration methods of carbon nanotube heat dissipation structures.

Description

An integration method of carbon nanotube heat dissipation structure and electronic device

technical field

The invention belongs to the technical field of microelectronic technology, and relates to an integration method of a carbon nanotube heat dissipation structure and an electronic device.

Background technique

With the development of microelectronic technology, the integration degree of microelectronic devices is getting higher and higher, resulting in an increasing power density inside the device. The huge power density makes the heat dissipation of the device an urgent problem to be solved, so the need for a new structure and process for the heat dissipation of the device is becoming more and more urgent.

Carbon nanotubes have high thermal conductivity (>1000W/mK) and are good heat dissipation materials; therefore, they have broad application prospects in heat dissipation devices for microelectronic devices. In microelectronics process, welding is a common structural connection method, but due to the chemical properties of carbon nanotubes themselves, it is difficult to directly connect carbon nanotubes to devices. The solution proposed so far is to adjust the process parameters in the preparation process of the carbon nanotube itself, so that the top of the free end of the carbon nanotube becomes an open structure to improve the wettability between the carbon nanotube and the solder. At the same time, in the welding process, the whole piece of carbon nanotubes with the growth substrate and the device need to be welded by reflow soldering, and then the carbon nanotubes and the substrate are separated, which increases the complexity of the process and reduces the production efficiency.

Contents of the invention

The invention provides an integration method of a carbon nanotube heat dissipation structure and an electronic device. The method deposits a metal wetting layer on the free end of the carbon nanotube array, then forms a solder layer on the wetting layer, and then grows the carbon nanotube array from The substrate is peeled off to form a heat dissipation structure, and finally welded directly to the metal wetting layer on the electronic device to realize the integration of the carbon nanotube heat dissipation structure and the electronic device.

Concrete technical scheme of the present invention is:

An integrated method of a carbon nanotube heat dissipation structure and an electronic device, as shown in Figure 1, comprising the following steps:

Step 1: Deposit a metal wetting layer.

A layer of metal with a thickness of 1-10 microns is deposited on the free end of the carbon nanotube array and the position on the electronic device where the heat dissipation structure needs to be integrated by sputtering or evaporation, as the wetting layer.

Step 2: Make the solder layer.

Spread the solder bar on the metal wetting layer deposited on the free end of the carbon nanotube array, heat at 230-300°C for 1-2 minutes, wait for the solder to melt and cover the entire metal wetting layer, then cool to room temperature to form a solder layer.

Step 3: forming a heat dissipation structure.

The growth substrate of the carbon nanotube array is fixed, and a pulling force is applied upward along the solder layer on the surface of the carbon nanotube array, so that the carbon nanotube array is separated from its own growth substrate to form a separate carbon nanotube heat dissipation structure.

Step 4: Integrate the heat sink.

Contact the solder layer of the carbon nanotube heat dissipation structure with the metal wetting layer deposited on the electronic device obtained in step 1, and heat at 230-350° C. for 1 to 2 minutes, so that the solder layer and the metal wetting layer on the electronic device are firm combined; then cooled to room temperature to realize the integration of the carbon nanotube heat dissipation structure and the electronic device.

In the above solution, the metals described in step 1 are Ni and Cr; the solder strips described in step 2 are Sn60/Pb40 tin-lead alloy strips.

The beneficial effects of the present invention are:

The method for integrating the heat dissipation structure of carbon nanotubes and electronic devices provided by the present invention adopts metal as the wetting layer, which can utilize the strong bonding force between carbon nanotubes and metals, and between metals and solder, so that solder can be firmly bonded to carbon nanotubes. The tube array is connected, so that the carbon nanotube heat dissipation structure can be directly welded with the electronic device, and there is no need to make specific requirements on the shape of the carbon nanotube itself. At the same time, the individual carbon nanotube heat dissipation structure obtained in step 3 can be prepared from a large-area carbon nanotube array to produce a large-area heat dissipation structure, and then use mechanical cutting to obtain small heat dissipation structures of different sizes or shapes, which overcomes the The traditional method needs to prepare a carbon nanotube array consistent with the size of the device, which simplifies the process and can also improve production efficiency; the use of strip solder to form a solder layer through direct heating and diffusion can also avoid the process brought by the reflow process complicate matters.

Description of drawings

Fig. 1 is a schematic flow chart of the present invention.

Fig. 2 is a test data diagram of the heat dissipation effect of the heat dissipation structure prepared in the present invention.

Detailed ways

The present invention will be further described below in conjunction with specific examples, but the present invention is not limited to the following examples.

A method for integrating a carbon nanotube heat dissipation structure and an electronic device, comprising the following steps:

1. Put the 8mm×8mm silicon dioxide chip with aligned carbon nanotube array and the silicon chip with Au thin film heating wire to be integrated into the radio frequency magnetron sputtering equipment, under Ar gas pressure 0.5Pa, power 100W Under the process conditions, a Ni metal target was used to sputter for 60 minutes, so as to deposit a Ni metal wetting layer with a thickness of about 5 microns on the top of the free end of the carbon nanotube and the back of the silicon wafer with the Au film heating wire.

2. Place the silicon dioxide wafer with the aligned carbon nanotube array on the hot stage, take three 8mm long Sb60/Pb40 solder strips, and spread them on the metal wetting layer of the carbon nanotube array. Set the temperature of the hot stage to 250°C. After the hot stage reaches the set temperature, wait for about two minutes. The solder will melt and flow to the entire surface of the metal-wetting layer. At this time, stop the heating of the hot stage and let it cool naturally.

3. After cooling to room temperature, use tweezers to apply an upward pulling force from the edge, and the entire carbon nanotube array can be separated from the growth substrate.

4. Place the silicon wafer with the Au thin film heating wire on which the metal wetting layer has been deposited on the hot stage. Place the carbon nanotube array solder layer facing down on the metal wetting layer of the silicon wafer, set the temperature of the hot stage to 250°C, wait for two minutes after the hot stage reaches the set temperature, stop the heating of the hot stage, and let it cool naturally. The tube cooling structure can be integrated with the silicon chip.

5. Determination of heat dissipation effect

The Agilent B2901A precision source meter is used to pass a certain power current on the thin film heating wire of the silicon wafer, and the standard four-wire method is used to measure the resistance of the heating wire. Since the temperature coefficient of Au is known, the temperature change of the heating wire can be calculated through the change of resistance. Figure 2(a) shows the temperature rise diagram of the heating wire without integrated heat dissipation structure, and Figure 2(b) shows the temperature rise diagram of the heating wire with heat dissipation structure, which shows that the integration of carbon nanotube heat dissipation structure and electronic devices can be effectively Reduce the temperature rise caused by the heating wire energization.

Those skilled in the art should know that the above examples mainly illustrate the effectiveness and practicability of the technical solution of the present invention, so as to verify the effect of the present invention, wherein the silicon wafer with Au thin film heating wire is not a further limitation on electronic devices. Those skilled in the art can realize the integration of the heat dissipation structure and the electronic device by selecting other metal materials or thin film preparation techniques to prepare the metal wetting layer, or selecting solder materials of other components according to the existing technology and common knowledge in the field.

Claims (3)

1. the integrated approach of a carbon nano-tube radiator structure and electronic device comprises the following steps:

Step 1: plated metal soakage layer;

The method of employing sputter or evaporation needs respectively the metal of position deposition one deck 1～10 micron thickness of integrated heat dissipation structure on carbon nano pipe array free end and electronic device, as soakage layer;

Step 2: make soldering-tin layer;

Soldering tin bar is laid on the metal infiltrating layer top that the carbon nano pipe array free end deposits, heated under 230～300 ℃ 1～2 minute, after scolding tin melts and covers whole metal infiltrating layer, be cooled to room temperature, form soldering-tin layer;

Step 3: form radiator structure;

The growth substrate of fixed carbon nano-tube array upwards applies pulling force along the surperficial soldering-tin layer of carbon nano pipe array, makes carbon nano pipe array separate with the growth substrate of himself, forms independent carbon nano-tube radiator structure;

Step 4: integrated heat radiating device;

The metal infiltrating layer that on the electronic device of the soldering-tin layer of carbon nano-tube radiator structure and step 1 gained, deposition is good is contacted, heated under 230～350 ℃ 1～2 minute, make the metal infiltrating layer strong bonded on soldering-tin layer and electronic device; Then be cooled to room temperature, realize the integrated of carbon nano-tube radiator structure and electronic device.

2. the integrated approach of carbon nano-tube radiator structure according to claim 1 and electronic device, is characterized in that, the described metal of step 1 is Ni or Cr.

3. the integrated approach of carbon nano-tube radiator structure according to claim 1 and electronic device, is characterized in that, the described soldering tin bar of step 2 is Sn60/Pb40 leypewter bar.

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