CN105984179A - Heat sink material and preparation method thereof - Google Patents

Abstract

The invention relates to a heat sink material, in particular to a heat sink material applied to micro-nano-scale power devices such as micro-nano optoelectronic devices, and a preparation method thereof, including a copper film layer and a graphene layer, and a copper film layer and graphite ene layers are alternately combined, and the copper thin film layer and the graphene layer are respectively more than 3 layers. The invention adopts a copper/graphene multi-layer structure, and realizes a copper/graphene multi-layer composite heat sink material by alternately preparing copper films and graphene. This invention takes advantage of the ultra-high thermal conductivity of graphene to grow graphene directly on the copper film layer, which solves the problem that graphene with a planar structure cannot be directly used as a heat sink material, and can achieve higher thermal conductivity; at the same time The heat sink material has good processability through the combination of graphene and copper.

Description

A kind of heat sink material and preparation method thereof

technical field

The invention relates to a heat sink material, in particular to a heat sink material applied to micro-nano-scale power devices such as micro-nano optoelectronic devices, and a preparation method thereof.

Background technique

In the past few decades, the continuous pursuit of the function and performance of microelectronic devices has made them develop in the direction of high density, high power and high speed, and their volume is also developing in the direction of miniaturization. At present, the feature size of semiconductors has tended to 100nm, which means that millions of micro devices can be used to complete the structure of chips. According to this trend, the heat generation will continue to increase, the heat flux of a single chip will far exceed 100W/cm ² , the multi-chip module will exceed 25 W/cm ² , and the printed circuit board will exceed 10 W/cm ² , this high-density and high-power demand makes microelectronic cooling technology one of the urgent issues to be solved.

The solution to the heat dissipation of microelectronic devices is to gradually transfer the heat generated by the working device to other media or the surrounding environment through the heat transfer element. In this heat dissipation, a direct heat sink with high thermal conductivity is required to be close to the For exothermic devices, the heat sink first absorbs the heat emitted by the device and then transfers it to the indirect heat sink. This direct heat sink is the heat sink material.

With the miniaturization and high-density and high-power development of high-performance electronic devices, heat sink materials with superior performance have become a key technology in microelectronics manufacturing. Carbon-based materials such as diamond and graphite have excellent thermal conductivity and are considered ideal heat sink materials. The thermal conductivity of highly oriented graphite is as high as 1100-1700W/mK in the transverse direction, but only 10-25W/mK in the longitudinal direction. Diamond has an isotropic thermal conductivity as high as 1100-1800W/mK. However, diamond is expensive and difficult to process, and it is difficult for a single diamond to be directly used as a heat sink material. Generally, diamond particles are combined with copper, aluminum and other metal materials to prepare composite heat sink materials, and the thermal conductivity is about 400-800 W/mK. However, there are great difficulties in the miniaturization process of this composite heat sink material. Processing is very difficult, and molded direct molding preparation is also difficult to achieve, so it cannot be applied to heat sink materials for micro-nano optoelectronic devices at present. Graphene is monoatomic layer graphite, a new type of thermal conductivity material with ultra-high thermal conductivity (~5000W/mK), and its two-dimensional single-layer carbon atom crystal structure endows it with flexible properties, making it easy to process , and is also easy to design and prepare microstructures, but the two-dimensional planar structure of single-layer carbon atoms makes it impossible to directly apply heat sink materials.

Contents of the invention

The purpose of the present invention is to address the deficiencies of the prior art, and provide a heat sink material that can be applied to micro-nano-scale power devices such as micro-nano optoelectronic devices, and has high thermal conductivity.

Another technical problem solved by the present invention is to provide a method for preparing a heat sink material with simple process and low cost.

In order to solve the above problems, the technical solution adopted in the present invention is:

A heat sink material includes a copper film layer and a graphene layer, and the copper film layer and the graphene layer are alternately combined, and the copper film layer and the graphene layer are respectively more than 3 layers.

A method for preparing a heat sink material, comprising the following steps:

a. Use a material with stronger chemical activity than copper and easy to react with acid or alkali as the substrate, and first use vacuum coating to deposit a certain thickness of copper film layer on the substrate;

b. Using transfer graphene method or chemical vapor deposition method to directly grow graphene on the copper film layer to form a graphene layer;

c. on the graphene layer obtained in the previous step, adopt vacuum coating to deposit a certain thickness of copper thin film layer;

d. Then adopt transfer graphene method or chemical vapor deposition to directly grow graphite on the copper film layer obtained in the previous step to form a graphene layer;

e. Repeat step c and step d in turn, repeat more than 1 time;

f. Finally removing the substrate with acid or base to obtain the heat sink material.

In the present invention, the thickness of the copper thin film layer obtained by vacuum coating is not greater than 10 μm.

In the present invention, graphene is directly grown on the copper film layer by chemical vapor deposition method, using methane and hydrogen as growth precursors, methane flow rate is 15-30 sccm, hydrogen flow rate is 40-60 sccm, growth temperature is 800°C-1080°C , the growth time is more than 30 minutes.

In the present invention, the substrate is aluminum or nickel, and is removed by dilute hydrochloric acid or dilute sulfuric acid.

In the present invention, the substrate is silicon and removed by sodium hydroxide or potassium hydroxide.

The beneficial effects of the present invention are:

The invention adopts a copper/graphene multi-layer structure, and realizes a copper/graphene multi-layer composite heat sink material by alternately preparing copper films and graphene. This invention takes advantage of the ultra-high thermal conductivity of graphene to grow graphene directly on the copper film layer, which solves the problem that graphene with a planar structure cannot be directly used as a heat sink material, and can achieve higher thermal conductivity; at the same time The heat sink material has good processability through the combination of graphene and copper. Good machinability makes it possible to achieve higher heat dissipation efficiency by designing microstructures, such as micro-groove heat dissipation structures. The heat sink material can be applied to heat sink heat dissipation of micro-nano-scale power devices such as micro-nano optoelectronic devices. Moreover, the preparation process of the present invention is simple, easy to operate, low in cost and high in product quality.

Description of drawings

Fig. 1 is a schematic diagram of the preparation process of the heat sink material of the present invention.

Fig. 2 is a schematic structural diagram of the heat sink material of the present invention.

Fig. 3 is a schematic diagram of a microgroove structure manufactured by the heat sink material of the present invention.

In the figure: 1. Graphene layer 2. Copper layer.

detailed description

What the present invention discloses is a kind of heat sink material, as shown in Figure 2, this heat sink material comprises copper thin film layer and graphene layer, and copper thin film layer and graphene layer are combined together alternately, this copper thin film layer and graphite The vinyl layers are three or more layers, respectively.

The present invention also discloses a preparation method of the above-mentioned heat sink material, the specific examples are as follows.

Example 1

The preparation process of the present invention is shown in Figure 1, comprises the following steps:

a. Using aluminum foil as the substrate, first prepare a copper film layer on the aluminum foil by vacuum evaporation method and a vacuum coating machine, control the background vacuum degree to 10 ^-2 Pa, the temperature is 1500 ° C, and deposit a thickness of 500nm on the aluminum foil. Copper film layer;

b. Using the chemical vapor deposition method and using a horizontal reactor to grow graphene on the copper film layer, using methane and hydrogen as the growth precursors, the methane flow rate is 20 sccm, the hydrogen gas flow rate is 50 sccm, the growth temperature is 1000 ° C, and the growth time is 30 minutes. Graphene is directly grown on the copper film to form a graphene layer;

c. After the growth is completed, the copper film layer is prepared by vacuum evaporation method and a vacuum coating machine. The background vacuum degree is controlled at 10 ^-2 Pa and the temperature is 1500 ° C. 500nm copper film layer;

d. Using chemical vapor deposition method and using a horizontal reactor to grow graphene on the copper film layer, using methane and hydrogen as growth precursors, methane flow rate 20sccm, hydrogen flow rate 50sccm, growth temperature 1000°C, growth time 30 minutes, Directly growing graphene on the copper film obtained in the previous step to form a graphene layer;

e. repeat step c and step d successively, repeat 20 times, realize copper/graphene multi-layer structure;

f. Finally, the aluminum foil is removed by etching with dilute hydrochloric acid (10-30%) to obtain the heat sink material ( FIG. 2 ).

The heat sink material prepared by this method can be processed into a micro-groove structure, as shown in FIG. 3 .

Example 2

The preparation process of the present invention is shown in Figure 1, comprises the following steps:

a. Using aluminum foil as the substrate, first prepare a copper film layer on the aluminum foil by vacuum evaporation method and a vacuum coating machine, control the background vacuum degree to 10 ^-2 Pa, the temperature is 1500 ° C, and deposit a thickness of 200nm on the aluminum foil. Copper film layer;

b. Using the chemical vapor deposition method and using a horizontal reactor to grow graphene on the copper film layer, using methane and hydrogen as the growth precursors, the methane flow rate is 20 sccm, the hydrogen gas flow rate is 50 sccm, the growth temperature is 1000 ° C, and the growth time is 30 minutes. Graphene is directly grown on the copper film to form a graphene layer;

c. After the growth is completed, the copper film layer is prepared by vacuum evaporation method and a vacuum coating machine. The background vacuum degree is controlled at 10 ^-2 Pa and the temperature is 1500 ° C. 200nm copper film layer;

d. Using chemical vapor deposition method and using a horizontal reactor to grow graphene on the copper film layer, using methane and hydrogen as growth precursors, methane flow rate 20sccm, hydrogen flow rate 50sccm, growth temperature 1000°C, growth time 30 minutes, Directly growing graphene on the copper film obtained in the previous step to form a graphene layer;

e. repeat step c and step d successively, repeat 50 times, realize copper/graphene multi-layer structure;

f. Finally, the aluminum foil is removed by etching with dilute hydrochloric acid (10-30%) to obtain the heat sink material ( FIG. 2 ).

The heat sink material prepared by this method can be processed into a micro-groove structure, as shown in FIG. 3 .

Example 3

The preparation process of the present invention is shown in Figure 1, comprises the following steps:

a. Using nickel foil as the substrate, first prepare a copper film layer on the nickel foil by vacuum evaporation method and a vacuum coating machine, control the background vacuum degree to 10 ^-2 Pa, and the temperature to 1500 ° C, deposit thickness on the nickel foil 200nm copper film layer;

b. Graphene is transferred on the copper film layer by graphene transfer method to form a graphene layer. The transfer process of the graphene transfer method is as follows: 1) First cut the copper foil with graphene into a square piece of 10×10cm; 2) Spin a layer of plexiglass with a spin coater at a speed of 3000 rpm for 1 min ;3) Drying treatment, temperature 100℃, time 30min; 4) Copper foil with graphene spin-coated with plexiglass on the upper surface was put into 20% nitric acid solution to corrode copper for 30min; Wash with ionized water for 3 times; 6) transfer the graphene supported by plexiglass to the copper film, heat treatment at 80°C for 20 minutes; 7) finally put in acetone solution to remove the plexiglass for 30 minutes;

c. After the transfer is completed, use the vacuum evaporation method and prepare a copper thin film layer through a vacuum coating machine. Control the background vacuum degree to 10 ^-2 Pa, and the temperature is 1500 ° C. Deposit thickness on the graphene layer obtained in the previous step. 200nm copper film layer;

d. adopt graphene transfer method to transfer graphene on the copper film layer obtained in the previous step to form a graphene layer;

e. repeat step c and step d successively, repeat 50 times, realize copper/graphene multi-layer structure;

f. Finally, use dilute hydrochloric acid (10-30%) to etch and remove the nickel foil to obtain the heat sink material (Figure 2).

The heat sink material prepared by this method can be processed into a micro-groove structure, as shown in FIG. 3 .

Example 4

The preparation process of the present invention is shown in Figure 1, comprises the following steps:

a. Using silicon as the substrate, first prepare a copper film layer on the silicon by vacuum evaporation method and a vacuum coating machine, control the background vacuum degree to 10 ^-2 Pa, the temperature is 1500 ° C, and deposit a thickness of 200nm on the silicon. Copper film layer;

b. Use the graphene transfer method to transfer graphene on the copper film layer to form a graphene layer. The transfer process of the graphene transfer method is as follows: 1) First cut the copper foil with graphene into a square piece of 10×10cm ; 2) Use a spin coater to spin-coat a layer of plexiglass at a speed of 3000 rpm for 1 minute; 3) Drying treatment at a temperature of 100°C for 30 minutes; 4) Spin-coat the organic glass on the upper surface with graphite Graphene copper foil was put into 20% nitric acid solution to corrode copper for 30 minutes; 5) Washed 3 times with deionized water; 6) Transfer graphene supported by plexiglass to copper film, heat treatment, temperature 80℃, Time 20min; 7) Finally put in acetone solution to remove plexiglass, time 30min;

c. After the transfer is completed, use the vacuum evaporation method and prepare a copper thin film layer through a vacuum coating machine. Control the background vacuum degree to 10 ^-2 Pa, and the temperature is 1500 ° C. Deposit thickness on the graphene layer obtained in the previous step. 200nm copper film layer;

d. adopt graphene transfer method to transfer graphene on the copper film layer obtained in the previous step to form a graphene layer;

e. repeat step c and step d successively, repeat 50 times, realize copper/graphene multi-layer structure;

f. Finally, remove silicon by etching with NaOH (20-40%) to obtain the heat sink material (Figure 2).

The heat sink material prepared by this method can be processed into a micro-groove structure, as shown in FIG. 3 .

Claims (6)

1. a heat sink material, it is characterised in that: including copper film layer and graphene layer, and copper film layer and graphene layer alternately combine, this copper film layer and graphene layer are respectively more than 3 layers.

The preparation method of a kind of heat sink material the most according to claim 1, it is characterised in that comprise the following steps:

A. chemism is used to be better than copper, it is easy to the material of acid or alkali reaction as substrate, first to use vacuum coating to deposit certain thickness copper film layer in substrate；

B. use Graphene transfer method on copper film layer, shift Graphene thus formed graphene layer or use chemical vapour deposition technique on copper film layer direct growth Graphene thus form graphene layer；

C. vacuum coating is used to deposit certain thickness copper film layer on the graphene layer obtained in previous step；

The most then use direct growth graphite on transfer Graphene method or the copper film layer that obtains in previous step of chemical vapour deposition technique thus form graphene layer；

E. it is repeated in step c and step d, is repeated 1 times above；

The most last acid or alkali are removed substrate thus are obtained described heat sink material.

The preparation method of a kind of heat sink material the most according to claim 2, it is characterised in that: the thickness of the copper film layer that described vacuum coating obtains is not more than 10 μm.

The preparation method of a kind of heat sink material the most according to claim 2, it is characterized in that: on described copper film layer, use chemical vapour deposition technique direct growth Graphene, with methane and hydrogen for growth presoma, methane flow is 15-30sccm, hydrogen flowing quantity 40-60sccm, growth temperature 800 DEG C-1080 degrees Celsius, growth time is more than 30 minutes.

The preparation method of a kind of heat sink material the most according to claim 2, it is characterised in that: described substrate is aluminum or nickel, and is removed by dilute hydrochloric acid or dilute sulfuric acid.

The preparation method of a kind of heat sink material the most according to claim 2, it is characterised in that: described substrate is silicon, and is removed by sodium hydroxide or potassium hydroxide.