High-power semiconductor laser stack array and packaging method thereof

Abstract

The invention relates to a high-power semiconductor laser stack array and a packaging method thereof, the stack array comprises a bar array, a water channel and an insulating sheet, the bar array is arranged on the upper side of the water channel through the insulating sheet, and the bar array adopts a form of sequentially stacking diamond copper, tungsten copper sheets, bars and tungsten copper sheets. The tungsten copper sheet and the diamond copper are combined as a heat sink. According to the invention, the heat dissipation efficiency of the bar is increased, the thermal expansion coefficient difference between the bar and the heat sink is reduced, and higher-power output of the laser is realized.

Description

Technical Field

[0001] The present invention relates to a high-power semiconductor laser module and a stacked array structure, belonging to the technical field of semiconductor lasers. Background Art

[0002] High-power semiconductor lasers are increasingly used in industrial processing, medical beauty, scientific research, military and other fields. With the expansion of applications and the continuous increase in market demand, the performance requirements for high-power lasers are getting higher and higher. High-power laser output requires efficient cooling technology as support. Currently, the main cooling methods are microchannel cooling and macrochannel cooling. In order to achieve higher power density and more compact packaging volume in the existing macrochannel packaging technology, most of the packaging structures stack the chips in the direction perpendicular to the chip surface to form a stacked array. Generally, the packaging structure is a small unit structure of heat sink - bar - heat sink, and then the small units are arranged and sintered into a stacked array, or heat sink - bar - heat sink - bar, arranged in sequence and sintered into a stacked array. During the sintering process, it is necessary to consider whether the thermal expansion coefficients of the heat sink material and the bar are close to prevent the stress generated from causing the bar to crack and bend, and a heat sink with high thermal conductivity can quickly diffuse the heat from the bar, which helps to reduce stress, improve the output efficiency, and increase the stability of the laser.

[0003] Currently, tungsten copper is usually used as the heat sink in the market. The thermal expansion coefficient of the tungsten copper heat sink is close to that of the bar. However, with the continuous improvement of the performance requirements for high-power semiconductors in the market, the thermal conductivity of the tungsten copper heat sink will not be able to meet the requirements of high-power output. Diamond copper has high thermal conductivity and has great application potential in bar packaging. However, the difference in thermal expansion coefficients between diamond copper and the bar is larger than the difference in thermal expansion coefficients between tungsten copper and the bar. Therefore, how to apply diamond to bar packaging is an urgent problem to be solved currently. Summary of the Invention

[0004] Aiming at the deficiencies of the prior art, the present invention provides a stacked array of high-power semiconductor lasers, adopting a packaging form of diamond copper - tungsten copper thin sheet - bar - tungsten copper thin sheet - diamond copper, which can not only reduce the difference in thermal expansion coefficients, but also increase the heat dissipation efficiency of the bar, achieve higher power output of the laser, and enhance the stability of the laser.

[0005] The present invention also provides a packaging method for the above-mentioned stacked array of high-power semiconductor lasers.

[0006] The present invention selects diamond copper - tungsten copper thin sheets as the heat sink, encapsulates tungsten copper with a thermal expansion coefficient closer to that of the bar on both sides of the bar to reduce the hard damage caused by stress to the bar, and then encapsulates diamond copper with better thermal conductivity on both sides of the tungsten copper. In order to achieve better heat conduction, tungsten copper thin sheets are used, and finally a small unit structure of diamond copper - tungsten copper thin sheet - bar - tungsten copper thin sheet - diamond copper is formed. In order to improve the packaging efficiency, an integrated packaging form with a narrower bar spacing and higher energy density is formed by stacking diamond copper - tungsten copper thin sheet - bar - tungsten copper thin sheet - diamond copper - tungsten copper thin sheet - bar - tungsten copper thin sheet - diamond copper... in sequence.

[0007] The present invention uses a gold - tin solder sintering array. The gold - tin solder used has high thermal conductivity, good mechanical strength, low contact resistance and long - term stability, and the gold - tin sintering process is very mature. Indium - silver solder with a lower melting point is used for secondary packaging between the silicon carbide insulating sheet and both the bar array and the water channel.

[0008] The technical solution of the present invention is as follows:

[0009] A high - power semiconductor laser stack array includes a bar array, a water channel and an insulating sheet. Among them, the bar array is arranged on the upper side of the water channel through the insulating sheet. The bar array adopts the form of stacking diamond copper - tungsten copper thin sheet - bar - tungsten copper thin sheet in sequence. The combination of the tungsten copper thin sheet and diamond copper is used as the heat sink. It not only has the similarity of the thermal expansion coefficient between tungsten copper and the bar, reducing the difference in thermal expansion coefficient to reduce the possibility of the bar cracking and bending deformation, but also has the good thermal conductivity of diamond copper, which can increase the heat dissipation efficiency of the bar.

[0010] Preferably according to the present invention, the thickness of the tungsten copper thin sheet is 130 um; the thickness of the diamond copper is 2 mm.

[0011] Preferably according to the present invention, the thermal expansion coefficient of the tungsten copper thin sheet is 4.5×10^ - 6 / °C, the thermal conductivity is 150 - 200 W / (m·K), the thermal expansion coefficient of the diamond copper is 1×10^ - 6 / °C, and the thermal conductivity is 2000 W / (m·K).

[0012] Preferably according to the present invention, the material of the bar is generally gallium arsenide, and the thermal expansion coefficient is 5.8×10^ - 6 / °C.

[0013] Preferably according to the present invention, the material of the insulating sheet is silicon carbide, which has high thermal conductivity. Moreover, due to better insulation, the thickness of the insulating sheet can be reduced, further improving the heat dissipation efficiency of the array.

[0014] The packaging method of the above - mentioned high - power semiconductor laser stack array is as follows:

[0015] (1) A gold-tin solder sheet is arranged between each layer of diamond copper, tungsten copper thin sheet, and bar, and they are arranged in sequence to form a bar array, and then sintered once in a vacuum eutectic furnace. The gold-tin solder used has high thermal conductivity, good mechanical strength, low contact resistance, and long-term stability, and the existing gold-tin sintering process is very mature;

[0016] (2) An indium-silver solder sheet is arranged between the insulating sheet, bar array, and water channel, and then put into a vacuum eutectic furnace for secondary sintering to complete the encapsulation.

[0017] The beneficial effects of the present invention are as follows:

[0018] 1. The present invention uses diamond copper - tungsten copper thin sheet as a heat sink, which can not only reduce the difference in thermal expansion coefficient but also increase the heat dissipation efficiency of the bar, realizing the output of higher power of the laser.

[0019] 2. The present invention uses silicon carbide as the insulating sheet. Its good thermal conductivity can spread heat at a high speed, improving the overall thermal conductivity. Moreover, due to its better insulation, the thickness of the insulating sheet can be reduced, further improving the heat dissipation efficiency of the array and optimizing the performance of the high-power semiconductor laser. Description of the Drawings

[0020] Figure 1 It is a schematic structural diagram of the bar array of the present invention;

[0021] Figure 2 It is a schematic structural diagram of the water channel of the present invention;

[0022] Among them, 1. Diamond copper; 2. Gold-tin solder sheet; 3. Tungsten copper thin sheet; 4. Solder sheet; 5. Bar; 6. Bar array; 7. Water channel; 8. Insulating sheet. Detailed Embodiments

[0023] The present invention will be further described below through embodiments in conjunction with the drawings, but not limited thereto.

[0024] Embodiment 1:

[0025] As Figure 1 shown, this embodiment provides a high-power semiconductor laser stack array, including a bar array 6, a water channel 7, and an insulating sheet 8. Among them, a bar array 6 is arranged on the upper side of the water channel 7 through the insulating sheet 8. The bar array 6 adopts the form of sequentially stacking diamond copper 1 - tungsten copper thin sheet 3 - bar 5 - tungsten copper thin sheet 3. The tungsten copper thin sheet 3 and the diamond copper 1 are combined as a heat sink, which not only has the similarity of the thermal expansion coefficients of tungsten copper and the bar, reducing the difference in thermal expansion coefficient to reduce the possibility of the bar cracking and bending deformation, but also has the good thermal conductivity of diamond copper, which can increase the heat dissipation efficiency of the bar.

[0026] The thickness of the tungsten copper thin sheet 3 is 130 um; the thickness of the diamond copper 1 is 2 mm.

[0027] The thermal expansion coefficient of the tungsten copper thin sheet 3 is 4.5*10^-6 / °C, the thermal conductivity is 150 - 200 W / (m*K), the thermal expansion coefficient of the diamond copper is 1*10^-6 / °C, and the thermal conductivity is 2000 W / (m*K).

[0028] The material of the bar 5 is generally gallium arsenide, and the thermal expansion coefficient is 5.8*10^-6 / °C.

[0029] The material of the insulating sheet 8 is silicon carbide, which has high thermal conductivity. Moreover, due to better insulation, the thickness of the insulating sheet can be reduced, further improving the heat dissipation efficiency of the array.

[0030] The packaging method of the above high-power semiconductor laser stack is as follows:

[0031] (1) Set gold-tin solder sheets 2 between each layer of diamond copper 1, tungsten copper thin sheet 3, and bar 5, and arrange them in sequence to form a bar array 6. Conduct a primary sintering in a vacuum eutectic furnace. The gold-tin solder used has high thermal conductivity, good mechanical strength, low contact resistance, and long-term stability, and the existing gold-tin sintering process is very mature;

[0032] (2) Set indium-silver solder sheets between the insulating sheet, bar array, and water channel, and then put them into a vacuum eutectic furnace for secondary sintering to complete the packaging.

[0033] The above are only the preferred embodiments of the present invention, and do not limit the patent scope of the present invention accordingly. All equivalent structural transformations made under the concept of the present invention by using the content of the specification and drawings of the present invention, or directly / indirectly applied in other related technical fields, are included in the patent protection scope of the present invention.

Claims

1. A high-power semiconductor laser stack, characterized in that: It includes a bar array, a water channel and an insulating sheet, wherein a bar array is arranged on the upper side of the water channel through the insulating sheet, and the bar array adopts the form of diamond copper-tungsten copper thin sheet-bar-tungsten copper thin sheet stacked in sequence, and the tungsten copper thin sheet is combined with diamond copper as a heat sink.

2. The high power semiconductor laser stack array as claimed in claim 1, characterized in that: The thickness of the tungsten copper sheet is 130um; the thickness of the diamond copper is 2mm.

3. The high power semiconductor laser stack array as claimed in claim 1, characterized in that: The thermal expansion coefficient of tungsten copper sheet is 4.5*10^-6 / ℃, and the thermal conductivity is 150-200W / (m*K). The thermal expansion coefficient of diamond copper is 1*10^-6 / ℃, and the thermal conductivity is 2000W / (m*K).

4. The high power semiconductor laser stack array as claimed in claim 1, characterized in that: The material of the bar is generally gallium arsenide, and the thermal expansion coefficient is 5.8*10^-6 / ℃.

5. The high power semiconductor laser stack array as claimed in claim 1, characterized in that: The insulating sheet is made of silicon carbide.

6. The packaging method of a high-power semiconductor laser array according to any one of claims 1 to 5, characterized in that: Here are the steps: (1) placing gold-tin solder sheets between each layer of diamond copper, tungsten copper sheet, and bar, arranging them in sequence to form a bar array, and performing a primary sintering in a vacuum eutectic furnace; (2) Indium silver solder sheets are placed between the insulating sheet, the bar array, and the water channel, and then placed in a vacuum eutectic furnace for secondary sintering to complete the packaging.

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