Preparation method of laser

Abstract

The invention relates to a preparation method of a laser. The preparation method comprises the following steps: S1, manufacturing a ridge waveguide on an epitaxial wafer; s2, manufacturing at least one protection column on the epitaxial wafer; s3, the bars made of the epitaxial wafer are stacked, the direction of the light emitting end is unified in the stacking process, and when the bars are stacked, protection columns are adopted to be supported between the upper layer bar and the lower layer bar; and S4, after the protection columns support the bars, a gap is formed between the upper layer bar and the lower layer bar, and the gap is located between every two adjacent protection columns. By manufacturing the protective columns, on one hand, the gaps for the protective layers to be arranged on the surfaces of the bars can be formed, and the protective layers can be arranged in the areas except the protective columns, so that the corrosion resistance and the low water absorption of the laser are improved under the non-airtight packaging condition, the reliability of the laser is improved, and the service life of the laser is prolonged; in the BAR strip stacking process, the design of the protection columns can replace the effect of strip accompanying, the number of arranged BARs of the laser BAR strips is increased, the strip clamping difficulty is reduced, and the production cost is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of optical communications, and in particular to a method for preparing a laser. Background Art

[0002] As the core foundation of the hardware facilities of 5G networks, optical modules are accelerating their evolution towards the high-speed transmission stage. The core optoelectronic chips need to be protected by airtight packaging to ensure the stable operation of the chips in outdoor signal base stations. However, expensive airtight packaging also makes companies bear a huge expenditure demand, so non-airtight packaging will also be a trend of cost reduction in the future, especially now that non-airtightly packaged lasers have been used in data centers. However, the premise of non-airtight packaging must be to ensure that optical devices (especially lasers) meet non-airtightness, which is undoubtedly a challenge.

[0003] By plating a passivation layer or a protective layer on the surface of the laser, the reliability of the chip can be effectively improved. The common method is to plate the corresponding optical passivation layer or protective layer on both ends of the laser BAR bar and the front of the chip. During the coating process at both ends of the cavity surface, in order to ensure the coating quality, the BAR bars cannot be placed continuously. A relatively short companion bar should be placed between the BAR bars to expose both ends of the BAR bar. Figure 1 After coating, the companion bar cannot be used multiple times, resulting in waste. At the same time, the use of the companion bar virtually reduces the number of laser BAR bars placed and reduces coating capacity. Summary of the invention

[0004] The object of the present invention is to provide a method for preparing a laser, which can at least solve some of the defects in the prior art.

[0005] To achieve the above object, the embodiment of the present invention provides the following technical solution: a method for preparing a laser, comprising the following steps: S1, fabrication of ridge waveguide on epitaxial wafer; S2, then forming at least one protection column on the epitaxial wafer; S3, stacking the bars made of the epitaxial wafers, unifying the direction of the light-emitting ends during the stacking process, and using the protection columns to support the bars between the upper and lower layers when the bars are stacked; S4, after the protection columns support the bar strips, a gap is formed between the upper and lower layers of the bar strips, and the gap is located between two adjacent protection columns.

[0006] Furthermore, a protective layer is provided on the surface of the bar except for the area occupied by the protective column.

[0007] Furthermore, the height of the protection column is greater than the height of the laser light emitting area, and the height of the protection column is 0.1-100 μm higher than the height of the light emitting area.

[0008] Furthermore, the protection column is manufactured on the same surface of the epitaxial wafer as the ridge waveguide, or the protection column is manufactured on a surface of the epitaxial wafer away from the ridge waveguide.

[0009] Furthermore, the protection column is in a strip shape, and the extending direction of the protection column is consistent with the extending direction of the ridge waveguide.

[0010] Furthermore, the protective column is in block shape.

[0011] Furthermore, the protection columns are fabricated on both sides of the ridge waveguide.

[0012] Furthermore, the protection column is manufactured in the electrode bonding area of ​​the bar.

[0013] Furthermore, the material of the protection column is one or more of metal material and insulating material.

[0014] Furthermore, after the protective layer is manufactured, an anti-reflection film and a high-reflection film are manufactured, and after the following processes, the laser is manufactured.

[0015] Compared with the prior art, the beneficial effects of the present invention are: a method for preparing a laser, by making a protective column, on the one hand, a gap can be formed for the protective layer to be arranged on the surface of the bar, and the protective layer can be arranged in any area except the protective column, so that the corrosion resistance and low water absorption of the laser are improved under non-airtight packaging conditions, thereby increasing the reliability and service life of the laser; on the other hand, in the process of BAR bar stacking, the design of the protective column can replace the role of the accompanying bar, increase the number of swinging BAR bars of the laser BAR bar, reduce the difficulty of clamping the bar, and reduce the production cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 Schematic diagram of the traditional laser bar stacking structure (front view); Figure 2 Schematic diagram of the traditional laser bar stacking structure (side view); Figure 3 This is an enlarged schematic diagram of the traditional laser cavity surface; Figure 4 A schematic diagram of a top view of a ridge waveguide of a method for preparing a laser provided in Embodiment 1 of the present invention; Figure 5 for Figure 4 AA section diagram of ; Figure 6 A schematic diagram of a top view of a protective column in a method for preparing a laser provided in Embodiment 1 of the present invention; Figure 7 for Figure 6AA section diagram of ; Figure 8 for Figure 6 BB section schematic diagram; Fig. 9 A schematic diagram of a top view of an electrode of a method for preparing a laser provided in Embodiment 1 of the present invention; Fig.10 for Fig. 9 AA section diagram of ; Fig.11 for Fig. 9 BB section schematic diagram; Fig.12 A schematic diagram of laser cavity facet stacking for a method for manufacturing a laser provided in Embodiment 1 of the present invention (front view); Fig.13 A schematic diagram of laser cavity facet stacking for a method for manufacturing a laser provided in Embodiment 1 of the present invention (side view); Fig.14 An enlarged schematic diagram of a laser cavity surface in a method for preparing a laser provided in Embodiment 1 of the present invention; Fig.15 A schematic diagram of a top view of a protective column in a method for preparing a laser provided in Embodiment 2 of the present invention; Fig.16 for Fig.15 AA section diagram of ; Fig.17 A schematic diagram of a top view of an electrode of a method for preparing a laser provided in Embodiment 2 of the present invention; Fig.18 for Fig.17 AA section diagram of ; Fig.19 for Fig.17 BB section schematic diagram; Fig. 20 A schematic diagram of laser cavity facet stacking for a method for preparing a laser provided in Embodiment 2 of the present invention (front view); Fig.21 A schematic diagram of laser cavity facet stacking for a method for manufacturing a laser provided in Embodiment 2 of the present invention (side view); Fig. 22 An enlarged schematic diagram of a laser cavity surface in a method for preparing a laser provided in Embodiment 2 of the present invention; Fig.23 A schematic diagram of a top view of a protective column in a method for preparing a laser provided in Embodiment 3 of the present invention; Fig.24 for Fig.23 AA section diagram of ; Fig.25 for Fig.23 BB section schematic diagram; Fig.26 A schematic diagram of a top view of an electrode of a method for preparing a laser provided in Embodiment 3 of the present invention; Fig. 27 for Fig.26 AA section diagram of ; Fig.28 for Fig.26 BB section schematic diagram; Fig.29 A schematic diagram of laser cavity facet stacking for a method for manufacturing a laser provided in Embodiment 3 of the present invention (front view); Fig.30 A schematic diagram of laser cavity facet stacking for a method for manufacturing a laser provided in Embodiment 3 of the present invention (side view); Fig.31 An enlarged schematic diagram of a laser cavity surface of a method for preparing a laser provided in Embodiment 3 of the present invention; Fig.32 A schematic diagram of a top view of a ridge waveguide of a method for manufacturing a laser provided in a fourth embodiment of the present invention; Fig.33 for Fig.32 AA section diagram of ; Fig.34 A schematic diagram of a top view of an electrode of a method for preparing a laser provided in a fourth embodiment of the present invention; Fig.35 for Fig.34 AA section diagram of ; Fig.36 A schematic diagram of the structure of a protective column on the back of a laser in a method for preparing a laser provided in a fourth embodiment of the present invention; Fig.37 for Fig.36 AA section diagram of ; Fig.38 A schematic diagram of a laser stack with a protective column on the back side of a laser preparation method provided in Embodiment 4 of the present invention (front view); Fig.39 A schematic diagram of a laser stack with a protective column on the back side of a laser preparation method provided in Embodiment 4 of the present invention (side view); In the figure numerals: 1 - bar; 2 - companion bar; 3 - ridge waveguide; 4 - guard column; 5 - electrode; 6 - back side of the laser. DETAILED DESCRIPTION

[0017] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0018] See also Figures 4 to 39 , an embodiment of the present invention provides a method for preparing a laser, comprising the following steps: S1, making a ridge waveguide 3 on an epitaxial wafer; S2, then making at least one protective column 4 on the epitaxial wafer; S3, stacking the bars 1 made from the epitaxial wafer, unifying the direction of the light-emitting end during the stacking process, and using the protective column 4 to support between the upper and lower layers of the bars 1 when each bar 1 is stacked; S4, after the protective column 4 supports the bar 1, a gap is formed between the upper and lower layers of the bar 1, and the gap is located between two adjacent protective columns 4. In this embodiment, by making the protective column 4, on the one hand, a gap can be formed for the protective layer to be arranged on the surface of the bar 1, and the protective layer can be arranged in all areas except the protective column 4, so that the corrosion resistance and low water absorption of the laser under non-airtight packaging conditions are improved, and the reliability and service life of the laser are increased. On the other hand, in the process of stacking BAR bars, the design of the protective column 4 can replace the role of the accompanying bar 2, increase the number of swinging BARs of the laser BAR bar, reduce the difficulty of clamping the bar, and reduce the production cost. Specifically, in the prior art, such as Figures 1 to 3 As shown, the contact area between the BAR bar and the companion bar 2 is large, and the contact area between the BAR bar and the companion bar 2 cannot be coated with a protective layer. Under non-airtight packaging conditions, the corrosion resistance is obviously not as high as that of the present embodiment, and thus the reliability and service life of the laser are not as high as that of the present embodiment. In this embodiment, the bar 1 is supported by a protective column 4. By designing the protective column 4, a gap can be formed between the upper and lower layers of the bar 1, and the gap is not only at the two ends of the bar 1, but also between two adjacent protective columns 4. This provides conditions for setting a protective layer in these gaps. If protective layers are also set in these gaps, the corrosion resistance of the laser can be greatly improved under non-airtight packaging conditions, increasing the reliability and service life of the laser. In addition, a number of protective columns 4 can also increase the number of swing bars of the laser BAR bar, reduce the difficulty of clamping the bar, and reduce production costs. Preferably, the material of the protective column 4 is one or more of a metal material and an insulating material, such as Si (silicon), SiO2 (silicon dioxide), SiN xetc., or polymer materials such as BCB (benzocyclobutene resin), Polyimide (PI, polyimide). The material of the protective column 4 can also be a combination of the above materials. Preferably, the laser is preferably an edge emitting laser, and can be applied to both edge emitting lasers in non-airtight packaging and edge emitting lasers in airtight packaging.

[0019] See also Figures 4 to 39 , a protective layer is provided on the surface of the bar 1 except for the area occupied by the protective column 4. In this embodiment, due to the presence of gaps, there are more areas between the stacked bars 1 for the material of the protective layer to enter. The protective layer is also called a passivation layer, which plays a protective role. When the protective column 4 structure is applied to an edge-emitting laser in a non-airtight package, a passivation layer or a protective layer needs to be plated on the cavity surface or the front surface.

[0020] See also Figures 4 to 39 The height of the protective column 4 is greater than the height of the laser light emitting area. To ensure the normal operation of the laser, preferably, the height of the protective column 4 is 0.1-100 μm higher than the height of the light emitting area.

[0021] See also Figures 4 to 39 , the protective column 4 is made on the same surface of the epitaxial wafer as the ridge waveguide 3, or the protective column 4 is made on the surface of the epitaxial wafer away from the ridge waveguide 3. Normally, the front side of the laser, the front side of the bar 1 and the front side of the epitaxial wafer, that is, the side on which the ridge waveguide 3 is made, is also the top surface of the laser bar 1 in the attached figure, while the back side of the laser, the back side of the bar 1 and the back side of the epitaxial wafer, that is, the side away from the ridge waveguide 3, is also the bottom surface of the laser bar 1 in the attached figure. In this embodiment, the position of the protective column 4 is not limited, and it can be on the front side of the laser or on the back side 6 of the laser. Embodiment 1, Embodiment 2 and Embodiment 3 are all embodiments in which the protective column 4 is made on the front side, and Embodiment 4 is an embodiment in which the protective column 4 is made on the back side.

[0022] See also Figures 4 to 39 , the protective column 4 is in the shape of a strip, and the direction in which the protective column 4 extends is consistent with the direction in which the ridge waveguide 3 extends. In this embodiment, the protective column 4 can adopt a strip structure, such as the strip structure shown in Example 1, Example 2, and Example 4. The overall length of the protective column 4 is elongated and in the shape of a long strip. The shape can be a hexahedral structure. For example, a prism structure is adopted, and the bottom and top surfaces of the prism are both square, and the bottom surface is larger than the top surface. There are multiple protective columns 4, and the long strip structure does not have more contact area with the bar 1. Of course, in addition to the above-mentioned regular shapes, irregular shapes can also be used as long as they can provide effective support.

[0023] See also Figures 4 to 39In this embodiment, the protective column 4 can adopt a block structure, or a structure similar to the above-mentioned hexahedron, except that the length is not so long, and the whole is a small block, such as the structural form shown in the third embodiment. Fig.26 As shown, only a small square can be seen from the top view. This block-shaped or dot-shaped protective column 4 can greatly increase the area covered by the protective layer, improve performance, and also help increase the number of BARs in the laser BAR bar. Of course, in addition to the above regular shapes, irregular shapes can also be used as long as they can be effectively supported.

[0024] See also Figures 4 to 39 , the protection columns 4 are made on both sides of the ridge waveguide 3. In this embodiment, the protection columns 4 can be made on both sides of the ridge waveguide 3. In another embodiment, the protection columns 4 can also be made in the electrode 5 wiring area of ​​the bar 1. The protection columns 4 belong to the clamp bar self-alignment design.

[0025] See also Figures 4 to 39 After the protective layer is made, the anti-reflection film and the high-reflection film are made, and after the next process, the laser is made.

[0026] The following is a specific implementation method:

[0027] Embodiment 1: A mask layer SiO2 is grown on the surface of the epitaxial wafer, and a ridge waveguide 3 is manufactured by combining photolithography and etching techniques, dry etching and wet etching techniques, as shown in FIG. Figure 4-5 ; Using photolithography technology, a protective column 4 of BCB material is fabricated along both sides of the ridge waveguide 3 and the electrode 5 wiring area. The height of the protective column 4 is greater than the height of the ridge waveguide 3. Figure 6-8 ; Using photolithography and etching technology, remove the SiO2 mask on the surface of the ridge waveguide 3 to complete the production of the electrical injection window; Using photolithography and etching technology, the electrode 5 pattern is made on the surface of the ridge waveguide 3 and the protection column 4 (the protection column 4 of the first embodiment is a combination of BCB material and metal material), and the metal is deposited by sputtering, evaporation, etc. Figure 9-11 .

[0028] After the electrode 5 metal is made, thinned, sputtered, alloyed, and stripped, the bar 1 and bar 1 are stacked in the coating fixture, and the light output direction is unified during the stacking process. Figure 12-14 .

[0029] In the coating equipment, a passivation layer or a protective layer is evaporated on the front and rear cavity surfaces of the bar 1 respectively. Due to the presence of the laser surface protection column 4, the passivation layer or the protective layer is plated on the cavity surface while the laser surface except the protection column 4 can be plated with the passivation layer or the protective layer.

[0030] After the cavity surface is plated with a passivation layer or a protective layer, an anti-reflection film and a high-reflection film are evaporated respectively, and the laser is completed.

[0031] Embodiment 2: A mask layer SiO2 is grown on the surface of the epitaxial wafer, and a ridge waveguide 3 is manufactured by combining photolithography and etching techniques, dry etching and wet etching techniques, as shown in FIG. Figure 4-5 ; Then, a plasma enhanced chemical vapor deposition (PECVD), atomic layer deposition (ALD) or evaporation equipment is used to grow a SiO2 protection column 4 on the entire surface, and the growth height thereof is greater than the height of the ridge waveguide 3; By using dry etching or wet etching technology, the SiO2 protection columns 4 (the material of the protection columns 4 in the second embodiment is SiO2) on both sides of the ridge waveguide 3 are retained. Figure 15-16 ; Grow the SiO2 mask layer again, and use photolithography and etching technology to remove the SiO2 mask layer on the surface of the ridge waveguide 3 to complete the production of the electrical injection window; Using photolithography and etching technology, the electrode 5 pattern is made on the surface of the ridge waveguide 3, and metal is deposited by sputtering, evaporation, etc. Figure 17-19 .

[0032] After the electrode 5 metal is made, thinned, sputtered, alloyed, and stripped, the bar 1 and bar 1 are stacked in the coating fixture, and the light output direction is unified during the stacking process. Figure 20-22 .

[0033] In the coating equipment, a passivation layer or a protective layer is evaporated on the front and rear cavity surfaces of the bar 1 respectively. Due to the presence of the laser surface protection column 4, the passivation layer or the protective layer is plated on the cavity surface while the laser surface except the protection column 4 can be plated with the passivation layer or the protective layer.

[0034] After the cavity surface is plated with a passivation layer or a protective layer, an anti-reflection film and a high-reflection film are evaporated respectively, and the laser is completed.

[0035] Embodiment 3 Based on Embodiment 2, there are four protective columns 4, which are distributed on both sides of the light-emitting area. Figure 23-31 .

[0036] Example 4: A mask layer SiO2 is grown on the surface of the epitaxial wafer, and a ridge waveguide 3 is produced by combining dry etching and wet etching using photolithography and etching techniques. Figure 32-33 ; The SiO2 mask layer is grown again, and the SiO2 mask layer on the surface of the ridge waveguide 3 is removed by photolithography and etching technology to complete the production of the electric injection window. Then, the electrode 5 pattern is produced on the surface of the ridge waveguide 3, and metal is deposited by sputtering, evaporation, etc. Figure 34-35 ; After the electrode 5 metal is made, it is thinned, and a metal seed layer is sputtered on the back side and then back lithography is performed. Combining lithography and electroplating or chemical plating processes, the metal is thickened in a local area on the back side 6 of the laser. At this time, the protective column 4 is on the back side 6 of the laser. Figure 36-37 ; In the coating fixture, the stacking of bar 1 and bar 1 is adopted, and the direction of the light output end is unified during the stacking process. Figure 38-39 .

[0037] In the coating equipment, a passivation layer or a protective layer is evaporated on the front and rear cavity surfaces of the bar 1 respectively. Due to the presence of the protective column 4 on the back side 6 of the laser, the passivation layer or the protective layer can be plated on the surface of the laser while the cavity surface is plated.

[0038] After the cavity surface is plated with a passivation layer or a protective layer, an anti-reflection film and a high-reflection film are evaporated respectively, and the laser is completed.

[0039] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for preparing a laser, characterized in that: The steps include: S1, fabrication of ridge waveguide on epitaxial wafer; S2, then forming at least one protection column on the epitaxial wafer; S3, stacking the bars made of the epitaxial wafers, unifying the direction of the light-emitting ends during the stacking process, and using the protection columns to support the bars between the upper and lower layers when the bars are stacked; S4, after the protection columns support the bar strips, a gap is formed between the upper and lower layers of the bar strips, and the gap is located between two adjacent protection columns.

2. The method for preparing a laser according to claim 1, characterized in that: A protective layer is provided on the surface of the bar except for the area occupied by the protective column.

3. The method for preparing a laser according to claim 1, characterized in that: The height of the protection column is greater than the height of the laser light emitting area, and the height of the protection column is 0.1-100 μm higher than the height of the light emitting area.

4. The method for preparing a laser according to claim 1, characterized in that: The protection column is manufactured on the same surface of the epitaxial wafer as the ridge waveguide, or the protection column is manufactured on the surface of the epitaxial wafer away from the ridge waveguide.

5. The method for preparing a laser according to claim 1, characterized in that: The protection column is in a strip shape, and the extending direction of the protection column is consistent with the extending direction of the ridge waveguide.

6. The method for preparing a laser according to claim 1, characterized in that: The protective column is in block shape.

7. The method for preparing a laser according to claim 1, characterized in that: The protection columns are made on both sides of the ridge waveguide.

8. A method for preparing a laser according to claim 1 or 7, characterized in that: The protection column is made in the electrode wiring area of ​​the bar.

9. The method for preparing a laser according to claim 1, characterized in that: The material of the protection column is one or more of metal material and insulating material.

10. The method for preparing a laser according to claim 2, characterized in that: After the protective layer is manufactured, the anti-reflection film and the high-reflection film are manufactured, and after the following processes, the laser is manufactured.

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