Semiconductor laser microchannel and batch preparation method

Abstract

The application discloses a semiconductor laser microchannel, the main structure of which is five layers, namely cooling liquid sealing layers located at upper and lower outer layers, upper and lower microchannel layers located at secondary inner layers and a guide layer arranged at an intermediate inner layer, and each layer is provided with a heat sink structure. The application further provides a method for batch preparing the semiconductor laser microchannel, in which the internal structure is first machined through a mother board, the whole is integrated through bonding, and a single heat sink is obtained through machining line cutting, so that the defects of small size of the microchannel heat sink on the market and time-consuming and laborious preparation are overcome.

Description

Technical Field

[0001] This invention belongs to the field of semiconductor technology, specifically relating to a semiconductor laser microchannel and its mass production method. Background Technology

[0002] Semiconductor lasers are widely used in fiber optic communication, optoelectronic integration, industrial processing, and medical fields. During operation, the heat generated by the chip is concentrated in the active region, which is on the order of several hundred micrometers, resulting in a high amount of heat concentrated in a small area. Temperature rise in the active region can reduce the laser's conversion efficiency, increase the threshold current, decrease the output power, cause a redshift in the lasing wavelength, and may even completely destroy the laser. Therefore, controlling the operating temperature of semiconductor lasers is crucial.

[0003] Currently, both passive and active heat sinks are used domestically and internationally to dissipate heat from semiconductor lasers. Passive heat sinks have limited heat dissipation capabilities and are generally suitable for cooling low-power continuous or ultrashort pulse high-power semiconductor lasers. However, for high-power continuous and quasi-continuous semiconductor laser arrays with even higher output power, efficient liquid coolers, i.e., active heat sinks, are used for heat dissipation. High-power semiconductor lasers on the market typically employ microchannel heat sinks. Microchannel heat sinks have low thermal resistance and rapidly remove heat through forced convection as the liquid flows through the microchannel, exhibiting strong heat dissipation capabilities; their heat transfer efficiency is tens of times that of ordinary cooling devices. However, commercially available microchannel heat sinks are small in size and their fabrication is time-consuming and labor-intensive. To improve efficiency, it is necessary to provide a semiconductor laser microchannel and a method for mass-producing such microchannels. Summary of the Invention

[0004] This invention addresses the shortcomings of existing semiconductor laser microchannels by providing a novel semiconductor laser microchannel and its mass production method. To achieve the above objective, the technical solution adopted by this invention is as follows:

[0005] In a first aspect, the present invention provides a semiconductor laser microchannel, the main structure of which is a five-layer motherboard made of oxygen-free copper, comprising a coolant sealing layer located on the upper and lower outer layers, an upper and lower microchannel layer located on the innermost layer, and a guiding layer disposed in the middle inner layer.

[0006] The thickness of each mother plate is 0.2 to 0.8 mm, and the upper coolant sealing layer mother plate is 0.05 to 0.1 mm thicker than the other mother plates. Each mother plate has multiple heat sink structures, the spacing between individual heat sink structures is 0.5 to 2 mm, and the outer edge distance of the mother plate is 15 mm to 30 mm.

[0007] Each heat sink structure within the coolant sealing layer includes, from top to bottom, a first heat sink hole, a second heat sink hole, a third heat sink hole, and two fourth heat sink holes, with the diameter ratio of the four types of heat sink holes being 4:2:4:1.

[0008] Each heat sink structure in the upper microchannel layer includes, from top to bottom, a bridge-shaped heat sink hole, a first heat sink hole, a second heat sink hole, a third heat sink hole, and two fourth heat sink holes. The diameter ratio of the four types of heat sink holes is 4:2:4:1.

[0009] Each heat sink structure in the lower microchannel layer includes a first U-shaped heat sink hole, a fifth heat sink hole disposed at the opening of the first U-shaped heat sink hole, a sixth circular heat sink hole disposed inside, and two seventh circular heat sink holes disposed on the lower side of the closed end of the U-shaped heat sink hole. The upper part of the fifth heat sink hole is comb-shaped, and the lower part is circular.

[0010] Each heat sink structure within the guide layer includes a second U-shaped heat sink hole, an eighth circular heat sink hole located at the opening of the second U-shaped heat sink hole, a ninth circular heat sink hole located inside, and two tenth circular heat sink holes located below the closed end of the U-shaped heat sink hole. The diameter ratio of the eighth, ninth, and tenth circular heat sink holes is 4:2:1.

[0011] Preferably, the upper part of the bridge-shaped heat sink hole is comb-shaped with equal lengths of teeth; the length of the teeth in the upper part of the fifth heat sink hole decreases from the center to both ends.

[0012] In a second aspect, the present invention provides a method for mass-producing the above-mentioned semiconductor laser microchannels. The method involves first fabricating the internal structure using a motherboard, then bonding the components together to form an integral structure, and finally obtaining individual heat sinks through machining and wire cutting. The specific steps are as follows:

[0013] A. Microchannel etching

[0014] After pretreatment, the motherboard undergoes sequential processes including lamination, exposure, development, etching, dimensional inspection, and post-processing to obtain the structure of each layer, as detailed below:

[0015] (1) Pretreatment: Use 5-20 vol% degreasing agent to prepare a degreasing solution; pickling process is as follows: use 0.01-0.02 wt% dilute sulfuric acid solution for pickling, temperature 20-40℃, soaking time is 30s-60s; micro-etching conditions are as follows: use 0.02-0.04 wt% sulfuric acid and 0.02-0.04 wt% sodium persulfate mixture, temperature 20-40℃, soaking time is 30s-100s; hot air drying temperature is 60~90℃;

[0016] (2) Film application: Use dry film with a thickness of 10μm-100μm;

[0017] (3) Exposure: A vacuum adsorption film exposure master plate structure is adopted, with an exposure energy of 40-100 J / cm. 2 ;

[0018] (4) Development: Use a weak alkaline solution (0.5-1.5wt% sodium carbonate or potassium carbonate solution) for development at a temperature of 20-50℃ for 1-5 minutes.

[0019] (5) Etching: Use a mixed solution of 10-30wt% hydrogen peroxide and 10-30wt% sodium chlorate for etching. The etching temperature is 20-50℃ and the etching time is 5-16min.

[0020] (6) Dimensional inspection: Etching tolerance not exceeding 0.05mm;

[0021] (7) Post-treatment: The process includes film removal, pickling, micro-etching, ultrasonic water washing, and hot air drying. The film removal conditions are as follows: 3-8wt% NaOH aqueous solution is used at a temperature of 30-60℃ for 1-5 min; the pickling, micro-etching, and hot air drying conditions are the same as the pre-treatment conditions.

[0022] B. Motherboard bonding

[0023] Bonding can be performed using either direct or indirect bonding methods;

[0024] Direct bonding, or copper oxidation sintering, involves first oxidizing the copper at 500-900℃ for 30-50 minutes in a nitrogen-oxygen atmosphere, and then sintering at 980-1098℃ for 1-5 hours in a nitrogen atmosphere.

[0025] Indirect bonding involves welding with solder, with the welding temperature controlled at 290℃-340℃ in a vacuum environment, and the welding time at 2-4 minutes.

[0026] C. Motherboard Surface Treatment

[0027] (1) Grinding and polishing: First, use 500-7000 grit sandpaper or abrasive disc to grind the upper surface to leave the thickness, and then use diamond polishing liquid with a particle size of 0.25-1.5μm to polish the surface; remove the thickness error controlled within 0.025mm, flatness <1μm, roughness <0.05μm;

[0028] (2) Surface nickel-gold plating: The nickel plating conditions are as follows: use a 0.28-0.32wt% nickel sulfate solution, control the pH value at 3.5-4, the temperature at 50-60℃, and the current density at 1.5-8A / dm³. 2 The nickel layer thickness is 2-5 μm;

[0029] The electroplating conditions for gold are as follows: using a 0.5-2wt% potassium gold cyanide solution, controlling the pH value to 3.5-4.5, the temperature to 40-60℃, and the current density to 0.5-1.2A / dm³. 2 The gold layer thickness is 0.05-0.5μm.

[0030] D. Air tightness test

[0031] The process of air tightness testing for P>0.8MPa is as follows: (1) Set horizontal axis points x1, x2, x3…x according to the product quantity and position. n The vertical axis points y1, y2, y3…y n (2) First, input constant air pressure along one axis direction of the mother plate internal channel and check the output air pressure. If the input and output air pressures are consistent, the air tightness of this column is qualified. When the output air pressure is lower than the input air pressure, there is a defect in this column. Then, input constant air pressure along the other axis direction of the mother plate internal channel. After comparing the input and output air pressures, find the column with defects and determine the defect location by the intersection of the X and Y axes.

[0032] F. Motherboard Cutting

[0033] The wire cutting method is used, and the following precision is controlled: the length and width errors are both kept within 0.025mm. Attached Figure Description

[0034] Figure 1 The diagram shows the structure of a semiconductor laser microchannel, where (a) is a schematic diagram of the overall structure and (b) is a schematic diagram of the layered structure.

[0035] Figure 2 This is a schematic diagram of the coolant sealing layer.

[0036] Figure 3 This is a schematic diagram of the microchannel layer structure;

[0037] Figure 4 This is a schematic diagram of the guide layer structure;

[0038] Figure 5 This is a schematic diagram of the structure of a single semiconductor laser microchannel after cutting;

[0039] Figure 6 This is a flowchart of the semiconductor laser microchannel fabrication process. Detailed Implementation

[0040] The present invention will now be described in detail with reference to the embodiments and accompanying drawings. However, it should be understood that the specific description below is illustrative and not restrictive, and should not be used to limit the scope of protection of the present invention.

[0041] according to Figure 1 The semiconductor laser microchannel 100 provided by the present invention has a main structure of a five-layer motherboard made of oxygen-free copper, namely a coolant sealing layer 1 located on the upper and lower outer layers, an upper and lower microchannel layer 2 located on the secondary inner layer, and a guide layer 3 located in the middle inner layer.

[0042] In terms of thickness, the upper coolant sealing layer substrate is 0.3mm thick, while the other four substrates are all 0.2mm thick. The spacing between individual heat sink structures within the structure is 1mm, and the outer edge distance of the substrate is 15mm.

[0043] The specific heat sink structure for each layer is as follows:

[0044] according to Figure 2 Each heat sink structure within the coolant sealing layer includes, from top to bottom, a first heat sink hole 11, a second heat sink hole 12, a third heat sink hole 13, and two fourth heat sink holes 14. The diameter ratio of the four types of heat sink holes is 4:2:4:1.

[0045] according to Figure 3 Each heat sink structure within the upper microchannel layer includes, from top to bottom, a bridge-shaped heat sink hole 21, a first heat sink hole 22, a second heat sink hole 23, a third heat sink hole 24, and two fourth heat sink holes 25. The upper portion of the bridge-shaped heat sink hole 21 is comb-shaped with equal-length teeth; the diameter ratio of the four types of heat sink holes is 4:2:4:1. The upper portion of the fifth heat sink hole...

[0046] Each heat sink structure within the lower microchannel layer includes a first U-shaped heat sink hole 26, a fifth heat sink hole 27 disposed at the opening of the first U-shaped heat sink hole, a sixth circular heat sink hole 28 disposed inside, and two seventh circular heat sink holes 29 disposed below the closed end of the U-shaped heat sink hole. The upper portion of the fifth heat sink hole 27 is comb-shaped, with the length of the comb teeth decreasing from the center to both ends, and the lower portion is circular. The diameter ratio of the sixth circular heat sink hole 28 and the seventh circular heat sink hole 29 is 2:1.

[0047] according to Figure 4 Each heat sink structure within the guide layer 3 includes a second U-shaped heat sink hole 31, an eighth circular heat sink hole 32 disposed at the opening of the second U-shaped heat sink hole, a ninth circular heat sink hole 33 disposed inside, and two tenth circular heat sink holes 34 disposed below the closed end of the U-shaped heat sink hole. The diameter ratio of the eighth circular heat sink hole 32, the ninth circular heat sink hole 33, and the tenth circular heat sink hole 34 is 4:2:1.

[0048] Furthermore, this invention provides a method for batch fabrication of semiconductor laser microchannels, the fabrication process of which is described below. Figure 6 :

[0049] 1. Chemical etching

[0050] After pretreatment, the motherboard undergoes sequential processes including lamination, exposure, development, etching, dimensional inspection, and post-processing to obtain the structure of each layer. The specific steps are as follows:

[0051] (1) Pretreatment of copper sheets: A 10 vol% degreasing agent solution was prepared to remove oil stains from the copper surface; then, the copper sheets were pickled with a 0.02 wt% dilute sulfuric acid solution at 30°C for 50 seconds; followed by micro-etching with a mixture of 0.04 wt% sulfuric acid and 0.04 wt% sodium persulfate at 30°C for 60 seconds, and then rinsed with overflow water and dried with hot air. (2) Film application: A 45 μm dry film was applied using a film application machine, and the film was exposed using a vacuum adsorption exposure machine at an exposure energy parameter of 70 J / cm. 2 (3) Development: Develop using 0.8wt% sodium carbonate solution at 40℃ for 1 min. (4) Etching: After development, etch using a mixture of 15wt% hydrogen peroxide and 15wt% sodium chlorate at 40℃ for 8 min, maintaining an etching accuracy within 0.05 mm. (5) Post-treatment of the etched copper sheet: stripping with 5wt% NaOH aqueous solution at 35℃ for 2 min, followed by acid washing, micro-etching, ultrasonic water washing, and hot air drying at 60-90℃.

[0052] 2. Chemical bonding

[0053] The etched motherboard is then processed according to the following... Figure 1 (b) shows the sequence of bonding completed by oxidation sintering. Oxidation was completed at 800°C for 40 min in a nitrogen atmosphere, and sintering was completed at 1080°C for 2 h in a nitrogen atmosphere.

[0054] 3. Surface treatment

[0055] After sintering, the mother plate is first sanded with 700, 4000, and 7000 grit sandpaper to create a 0.3mm sealing layer, and then polished with 1.5 and 0.5μm diamond polishing paste. The thickness is controlled within 0.025mm, the flatness is less than 1μm, and the roughness is less than 0.05μm.

[0056] The surface is plated with a 3μm nickel layer and a 0.5μm gold layer. The nickel plating uses a 0.28wt% nickel sulfate solution, with the pH value controlled at 3.5-4, the temperature at 55℃, and the current density at 5A / dm³. 2 Electroplating gold uses a 1wt% potassium gold cyanide solution, with the pH value controlled at 3.5-4.5, the temperature at 50℃, and the current density at 1.2A / dm³. 2 .

[0057] 4. Air tightness test

[0058] like Figure 1(b) Set the horizontal axis (x1, x2, x3… x9) and the vertical axis (y1, y2, y3… y6) according to the product quantity and position. Input 1 MPa air pressure into the internal channel of the motherboard along the vertical axis and check the output air pressure. When the input and output air pressures are consistent, the airtightness of this column is qualified; when the output air pressure is lower than the input air pressure, there is a defect in this column. Then, input a constant air pressure into the internal channel of the motherboard along the horizontal axis and find the defective columns by comparing the input and output air pressures. Determine the defect location by intersecting the X and Y axes.

[0059] 5. Target cutting

[0060] Finally, wire cutting is performed on the motherboard to obtain semiconductor laser heat sink products, such as... Figure 5 The image shows a single microchannel. During cutting, the length error should be within 0.025mm, and the width error should be within 0.025mm.

[0061] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of this invention is defined by the appended claims and their equivalents.

Claims

1. A semiconductor laser microchannel, characterized in that, The main structure consists of five layers: upper and lower outer coolant sealing layers, upper and lower microchannel layers in the next innermost layer, and a guiding layer in the middle innermost layer. The thickness of each mother plate is 0.2~0.8mm, and the upper coolant sealing layer mother plate is thicker than the other mother plates; Each heat sink structure within the coolant sealing layer includes, from top to bottom, a first heat sink hole, a second heat sink hole, a third heat sink hole, and two fourth heat sink holes. The diameter ratio of the four types of heat sink holes is 4:2:4:

1. Each heat sink structure within the upper microchannel layer of the upper and lower microchannel layers includes, from top to bottom, a bridge-shaped heat sink hole, a first heat sink hole, a second heat sink hole, a third heat sink hole, and two fourth heat sink holes. The diameter ratio of the four types of heat sink holes is 4:2:4:

1. Each heat sink structure within the lower microchannel layer of the upper and lower microchannel layers includes a first U-shaped heat sink hole, a fifth heat sink hole disposed at the opening portion of the first U-shaped heat sink hole, a sixth circular heat sink hole disposed inside, and two seventh circular heat sink holes disposed below the closed end of the U-shaped heat sink hole. The upper portion of the fifth heat sink hole is comb-shaped, and the lower portion is circular. Each heat sink structure within the guide layer includes a second U-shaped heat sink hole, an eighth circular heat sink hole located at the opening of the second U-shaped heat sink hole, a ninth circular heat sink hole located inside, and two tenth circular heat sink holes located below the closed end of the U-shaped heat sink hole. The diameter ratio of the eighth, ninth, and tenth circular heat sink holes is 4:2:

1.

2. The semiconductor laser microchannel according to claim 1, characterized in that: in, The material of the coolant sealing layer, microchannel layer, and guide layer substrate is oxygen-free copper. The upper coolant sealing layer is 0.05~0.1mm thicker than the other layers.

3. The semiconductor laser microchannel according to claim 1, characterized in that: in, The spacing between individual heat sink structures within each motherboard layer is 0.5~2mm, and the outer edge distance of the motherboard is 15mm~30mm.

4. The semiconductor laser microchannel according to claim 1, characterized in that: in, The upper part of the bridge-shaped heat sink hole is comb-shaped, and the comb teeth are of equal length; The length of the comb teeth at the upper part of the fifth heat sink hole decreases from the center to both ends.

5. A method for batch fabrication of the semiconductor laser microchannels according to any one of claims 1 to 4, characterized in that, Includes the following steps: A. Microchannel etching After pretreatment, the motherboard undergoes sequential processes including lamination, exposure, development, etching, dimensional inspection, and post-processing to obtain the structure of each layer. The pretreatment process includes degreasing, pickling, micro-etching with a mixture of sulfuric acid and sodium persulfate, overflow rinsing, and hot air drying. When applying the film, use dry film with a thickness of 10μm-100μm; The exposure process employs a vacuum adsorption film exposure master plate structure, with an exposure energy of 40-100 J / cm². 2 ; During development, a weakly alkaline solution is used, the temperature is 20-50℃, and the development time is 1-5 minutes. During etching, a mixed solution of 10-30wt% hydrogen peroxide and 10-30wt% sodium chlorate is used for etching. The etching temperature is 20-50℃ and the etching time is 5-16min. Dimensional inspection: Etching tolerance not exceeding 0.05mm; The post-processing process includes, in sequence, film removal, pickling, micro-etching, ultrasonic water washing, and hot air drying. B. Motherboard bonding Bonding can be performed using either direct or indirect bonding methods; For direct bonding, copper oxidation is first completed in a nitrogen-oxygen atmosphere, followed by copper sintering in a nitrogen atmosphere; for indirect bonding, solder welding is used. C. Motherboard Surface Treatment (1) Grinding and polishing: First, use 500-7000 grit sandpaper or abrasive disc to grind the upper surface to leave the thickness, and then use diamond polishing liquid with a particle size of 0.25-1.5μm to polish the surface; remove the thickness error controlled within 0.025mm, flatness <1μm, roughness <0.05μm; (2) Surface plating with nickel and gold: nickel layer thickness 2-5μm, gold layer thickness 0.05-0.5μm; D. Air tightness test The air pressure is checked along the X and Y axes in the longitudinal and transverse directions of the motherboard. When the output air pressure is lower than the input air pressure, the defect location is confirmed. E. Motherboard Cutting The wire cutting method is used, and the following precision is controlled: the length and width errors are both kept within 0.025mm.

6. The method for semiconductor laser microchannels according to claim 5, characterized in that: in, In step A, the preprocessing procedure is as follows: Degreasing is performed using a 5-20 vol% degreasing agent solution; the pickling process is as follows: pickling is performed using a 0.01-0.02 wt% dilute sulfuric acid solution at a temperature of 20-40℃ for 30-60 seconds; the micro-etching conditions are as follows: micro-etching is performed using a mixture of 0.02-0.04 wt% sulfuric acid and 0.02-0.04 wt% sodium persulfate at a temperature of 20-40℃ for 30-100 seconds; the hot air drying temperature is 60-90℃. Use a 0.5-1.5 wt% sodium carbonate or potassium carbonate solution for development; The post-treatment process is as follows: the film removal treatment conditions are as follows: 3-8 wt% NaOH aqueous solution is used, the temperature is 30-60℃, and the soaking time is 1-5 min; the acid washing, micro-etching, and hot air drying conditions are the same as the pretreatment.

7. The method for semiconductor laser microchannels according to claim 5, characterized in that: in, In step B, Direct bonding, or copper oxidation sintering, involves first oxidizing the copper at 500-900℃ for 30-50 minutes in a nitrogen-oxygen atmosphere, and then sintering at 980-1098℃ for 1-5 hours in a nitrogen atmosphere. Indirect bonding involves welding with solder, with the welding temperature controlled at 290℃-340℃ in a vacuum environment, and the welding time at 2-4 minutes.

8. The method for semiconductor laser microchannels according to claim 5, characterized in that: in, In step C, During grinding and polishing: first grind the upper surface to 0.3mm using 700, 4000, and 7000 grit sandpaper, and then polish the surface using diamond polishing fluid with a particle size of 1.5 and 0.5μm respectively; The nickel electroplating conditions are as follows: a 0.28-0.32 wt% nickel sulfate solution is used, the pH value is controlled at 3.5-4, the temperature is 50-60℃, and the current density is 1.5-8 A / dm³. 2 ; The electroplating conditions for gold are as follows: using a 0.5-2wt% potassium gold cyanide solution, controlling the pH value to 3.5-4.5, the temperature to 40-60℃, and the current density to 0.5-1.2A / dm³. 2 .

9. The method for semiconductor laser microchannels according to claim 5, Its features are: in, In step D, the airtightness test: the process of airtightness test for P>0.8MPa is as follows: (1) Set the horizontal axis points x1, x2, x3…x according to the product quantity and position. n The vertical axis points y1, y2, y3…y n (2) First, input constant air pressure into the internal channel of the mother plate along one of the axes and check the output air pressure. If the input and output air pressures are consistent, then the air tightness of this column is qualified. When the output air pressure is lower than the input air pressure, there is a defect in this column. Then, a constant air pressure is input into the internal channel of the motherboard along the other axis. The defective column is found by comparing the input and output air pressures, and the defect location is determined by the intersection of the X and Y axes.

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