Laser, wafer and laser chip

Abstract

The present invention provides a laser, a wafer and a laser chip. The laser includes: a laser chip and a heat sink. The laser chip includes a main chip area, a first cleavage area and a second cleavage area. The first cleavage area is adjacent to the main chip area, and the first cleavage area has a light-emitting end face for emitting light. The second cleavage area is adjacent to an end of the main chip area away from the first cleavage area. The first cleavage area has a first cleavage length, and the second cleavage area has a second cleavage length. The heat sink is bonded to the main chip area and the second cleavage area. The first cleavage length is smaller than the second cleavage length, and the heat sink is spaced apart from the first cleavage area. The laser of the present invention solves the technical problem of poor heat dissipation of the laser.

Description

Technical Field

[0001] The present invention relates to the technical field of semiconductor chips, and in particular to a laser, a wafer and a laser chip. Background Art

[0002] The laser chip forms the necessary resonant cavity structure of the laser by depositing an anti-reflection film in the front cavity and a high-reflection film in the back cavity, so that the photon energy can be repeatedly oscillated in the cavity and then emit laser after exceeding the threshold critical point.

[0003] like Figure 13 After the laser chip components are cleaved and laminated, they need to be soldered to the heat sink. Figure 13 When soldering in the same way, that is, the AR (anti-reflection) end cleavage area and the AR film are not suspended on the heat sink, the liquid solder material will overflow during the soldering process, forming solder overflow 1-1 on the front end of the AR surface 1-2 and solder overflow 1-1 on the rear end of the HR surface 1-3. The overflow solder 1-1 will cover the front end of the AR film and the rear end of the HR surface 1-3. Since the front end of the AR film needs to emit light, the solder overflowing to the front end of the AR film will block the light output and affect the overall performance. In order not to affect the light output effect of the front end of the AR film, it is necessary to Figure 14 As shown, the AR film and the AR end cleavage region, that is, the AR surface 1-2, are suspended relative to the heat sink. However, the AR film and the AR end cleavage region are not attached to the heat sink, and heat is accumulated in the AR film and the AR end cleavage region, thereby increasing the temperature of the light-emitting end face of the AR film and reducing the reliability of the laser.

[0004] Also, see Figure 15 In the process of manufacturing wafers into laser chips, a cleave mark is set in the middle position between the front cavity surface of the front bar (i.e., the bar strip) and the back cavity surface of the back bar. Along the middle cleave mark, the wafer is cleaved into independent bar devices using a dicing and splitting process, and then laminated in the form of stacked bars. The conventional design is that the AR end cleave area and the HR end cleave area are at the same distance from the cleave mark. However, as mentioned above, after the lamination is completed, the AR film and the AR end cleave area after packaging with the heat sink are not bonded to the heat sink, and therefore cannot be directly connected to the heat sink for heat dissipation. When the cleave area at the same distance is retained, the longer length of the AR end cleave area will cause the near-cavity surface temperature to increase, reducing its COMD level and thus reducing reliability. Summary of the Invention

[0005] The purpose of the present invention is to overcome the above technical deficiencies and provide a laser, a wafer and a laser chip to solve the technical problem of poor heat dissipation of the laser in the related art.

[0006] In order to achieve the above technical objectives, the present invention adopts the following technical solutions: a laser, comprising: a laser chip and a heat sink, the laser chip comprising a main chip area, a first cleavage area and a second cleavage area; the first cleavage area is adjacent to the main chip area, and the first cleavage area has a light-emitting end face for emitting light; the second cleavage area is adjacent to an end of the main chip area away from the first cleavage area; along the light-emitting direction of the laser, the length of the first cleavage area is a first cleavage length, and the length of the second cleavage area is a second cleavage length; the first cleavage length is smaller than the second cleavage length; a heat sink, the heat sink is at least in contact with the main chip area; the heat sink is spaced apart from at least part of the first cleavage area.

[0007] Furthermore, the heat sink includes: a heat sink bonding surface, which is used to bond with the main chip area and the second cleavage area; wherein the plane where the heat sink bonding surface is located is the heat sink target plane; the orthographic projection of the first cleavage area on the heat sink target plane is a first non-overlapping area; at least a part of the first non-overlapping area does not overlap with the orthographic projection of the heat sink on the heat sink target plane, and the orthographic projection of the second cleavage area on the heat sink target plane is a first overlapping area; the first overlapping area overlaps with the orthographic projection of the heat sink on the heat sink target plane.

[0008] Furthermore, the heat sink includes a heat sink normal plane; the heat sink normal plane laser is perpendicular to the heat sink target plane; the heat sink normal plane is perpendicular to the light output end face, the length of the projection of the first non-overlapping area on the heat sink normal plane is the first non-overlapping length D1, and the length of the projection of the first overlapping area on the heat sink normal plane is the first non-overlapping length D2; wherein, the first non-overlapping length D1 is equal to the first cleavage length, and the first overlapping length D2 is equal to the second cleavage length.

[0009] Furthermore, a ratio of the first non-overlapping length D1 to the first overlapping length D2 is less than or equal to 3 / 17.

[0010] Furthermore, the laser chip also includes an anti-reflection film and a high-reflection film. In the light-emitting direction, the anti-reflection film is adjacent to the first cleavage region, and in the opposite direction of the light-emitting direction, the high-reflection film is adjacent to the second cleavage region. Along the light-emitting direction of the laser, the length of the anti-reflection film is a first anti-reflection length, and the length of the high-reflection film is a first high-reflection length; wherein, the first anti-reflection length is less than the first high-reflection length.

[0011] Furthermore, the orthographic projection of the antireflection film on the heat sink target plane does not overlap with the orthographic projection of the heat sink on the heat sink target plane; the orthographic projection of the high reflection film on the heat sink target plane overlaps with the orthographic projection of the heat sink on the heat sink target plane.

[0012] Furthermore, the orthographic projection of the antireflection film on the heat sink target plane is a second non-overlapping area, and the area where the orthographic projection of the high-reflection film on the heat sink target plane overlaps with the orthographic projection of the heat sink on the heat sink target plane is the second overlapping area; the projection length of the second non-overlapping area on the heat sink normal plane is the second non-overlapping length D3, and the projection length of the second overlapping area on the heat sink normal plane is the second overlapping length D4; wherein, the second non-overlapping length D3 is equal to the first antireflection length, and the second overlapping length D4 is equal to the first high-reflection length.

[0013] Furthermore, a ratio of the second non-overlapping length D3 to the second overlapping length D4 ranges from 0.1 to 0.2.

[0014] Furthermore, the sum of the first non-overlapping length D1 and the second non-overlapping length D3 is the third non-overlapping length, and the sum of the first overlapping length D2 and the second overlapping length D4 is the third overlapping length, wherein the ratio of the third overlapping length to the third non-overlapping length ranges from 5 to 10.

[0015] Furthermore, the anti-reflection film also includes a first anti-reflection surface, which is a surface away from the first cleavage region along the light-emitting direction, and the first anti-reflection surface has a first anti-reflection temperature; the high-reflection film also includes a first high-reflection surface, which is a surface away from the second cleavage region along the light-emitting direction, and the first high-reflection surface has a first high-reflection temperature; wherein, when the laser emits light, the difference between the first anti-reflection temperature and the first high-reflection temperature is less than 45°C.

[0016] A wafer includes multiple laser chips. The wafer is used to manufacture laser chips, and at least two laser chips are cleaved from the wafer; a first cleavage region of one of two adjacent laser chips on the wafer is connected to a second cleavage region of the other of the two adjacent laser chips.

[0017] A laser chip, comprising a main chip region, a first cleavage region, and a second cleavage region; the first cleavage region is adjacent to the main chip region, and the first cleavage region has a light-emitting end face for emitting light; the second cleavage region is adjacent to an end of the main chip region away from the first cleavage region; along the light-emitting direction of the laser, the length of the first cleavage region is a first cleavage length, and the length of the second cleavage region is a second cleavage length; the first cleavage length is smaller than the second cleavage length; the laser chip comprises a single tube or a bar. Beneficial effects

[0018] 1. The laser of the present invention includes: a laser chip and a heat sink, the laser chip includes a main chip area, a first cleavage area and a second cleavage area; the first cleavage area is adjacent to the main chip area, and the first cleavage area has a light-emitting end face for emitting light; the second cleavage area is adjacent to an end of the main chip area away from the first cleavage area; along the light-emitting direction of the laser, the length of the first cleavage area is a first cleavage length, and the length of the second cleavage area is a second cleavage length; the first cleavage length is smaller than the second cleavage length; a heat sink, the heat sink is at least in contact with the main chip area; the heat sink is spaced apart from at least part of the first cleavage area. In a wafer including a laser chip, the cleavage marks of the bars located at the front and rear positions are adjusted from the traditional even distribution in the middle to one side close to the front cavity surface (AR end cleavage area). Therefore, fewer cleavage areas that are not bonded to the heat sink are retained on the front cavity surface, and more cleavage areas that are bonded to the heat sink are retained on the rear cavity surface, thereby forming an asymmetric cleavage area structure. In the light output direction, the length of the first cleavage area is reduced, thereby reducing the volume of the first cleavage area, reducing the energy concentration in the first cleavage area, and reducing the temperature of the first cleavage area, thereby ensuring the performance of the laser and solving the problem of poor heat dissipation of the laser chip with a symmetrical cleavage area and the laser using the laser chip.

[0019] 2. The surface of the main chip area of ​​the laser of the present invention is covered with a metal layer. The asymmetric structure of the cleavage area formed on the opposite sides of the metal layer on the main chip area increases the length of the cleavage area at the HR end. When laminating, it can effectively accommodate the film turning over so that it will not reach the metal area, thereby reducing the defective rate caused by the film turning over. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 1 is a schematic structural diagram of a laser used in an embodiment of the present invention from one viewing angle;

[0021] Figure 2 is a schematic structural diagram of a laser used in an embodiment of the present invention from another perspective;

[0022] Figure 3 is a side view of a laser used in an embodiment of the present invention;

[0023] Figure 4 Schematic diagram of the structure of a laser chip used in an embodiment of the present invention;

[0024] Figure 5 Schematic diagram of the structure of a heat sink for a laser provided in an embodiment of the present invention;

[0025] Figure 6 A schematic structural diagram of a heat sink bonding surface of a laser provided in an embodiment of the present invention;

[0026] Figure 7A schematic structural diagram of the side of a heat sink of a laser provided in an embodiment of the present invention;

[0027] Figure 8 A schematic structural diagram of a first non-overlapping region and a first overlapping region of a laser provided in an embodiment of the present invention;

[0028] Figure 9 A schematic structural diagram of the projection of the first non-overlapping region and the first overlapping region of the laser provided in an embodiment of the present invention;

[0029] Figure 10 A schematic diagram of the structure of the second non-overlapping region and the second overlapping region of the laser provided in an embodiment of the present invention;

[0030] Figure 11 A schematic structural diagram of the projection of the second non-overlapping region and the second overlapping region of the laser provided in an embodiment of the present invention;

[0031] Figure 12 Is a schematic structural diagram of a wafer provided in an embodiment of the present invention;

[0032] Figure 13 This is a schematic diagram of the structure in which the laser chip is not suspended on the heat sink in the prior art;

[0033] Figure 14 This is a schematic diagram of the structure of a laser chip suspended on a heat sink in the prior art;

[0034] Figure 15 It is a schematic diagram of the structure of a wafer in the prior art.

[0035] The above drawings include the following reference numerals:

[0036] 10. Laser chip; 20. Heat sink; 30. Cleavage mark;

[0037] 1. Main chip area;

[0038] 2. First cleavage region; 21. Light-emitting end face; 22. Heat sink bonding surface; 23. Heat sink target plane; 24. Heat sink normal plane; 25. Second cleavage region; 26. Side surface;

[0039] 3. First non-overlapping area; 4. First overlapping area; 5. Anti-reflection film; 51. First anti-reflection surface; 6. High-reflection film; 61. First high-reflection surface; 7. Second non-overlapping area; 8. Second overlapping area;

[0040] 1-1, overflow solder; 1-2, AR side; 1-3, HR side. DETAILED DESCRIPTION

[0041] In order to enable those skilled in the art to better understand the present invention, the following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the drawings 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 in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts should fall within the scope of protection of this application.

[0042] See also Figures 1 to 12 According to an embodiment of the present invention, a laser is provided. Preferably, the laser is a semiconductor laser, comprising: a laser chip 10 and a heat sink 20, wherein the laser chip 10 comprises a main chip region 1, a first cleavage region 2 and a second cleavage region 25; the main chip region 1 comprises a metal layer; the first cleavage region 2 is adjacent to the main chip region 1, and the first cleavage region 2 has a light-emitting end face 21 for emitting light; the second cleavage region 25 is adjacent to an end of the main chip region 1 away from the first cleavage region 2; along the light-emitting direction of the laser, the length of the first cleavage region is a first cleavage length, and the length of the second cleavage region is a second cleavage length; the first cleavage length is smaller than the second cleavage length; a heat sink, wherein the heat sink is at least in contact with the main chip region; the heat sink is spaced apart from at least part of the first cleavage region. The heat sink 20 is bonded to the main chip area 1. Preferably, the heat sink is bonded to the metal layer of the main chip area. Preferably, the heat sink is connected to the second cleavage area 25. The connection here includes but is not limited to the heat sink being bonded or not bonded to the second cleavage area 25. The first cleavage length is smaller than the second cleavage length, and the heat sink 20 is spaced apart from the first cleavage area 2. It should be understood that a metal layer is provided on both the upper and lower sides of the main chip area of ​​the laser chip of the present application.

[0043] It should be noted that the heat sink 20 of this embodiment is spaced apart from the first cleavage region 2, which means that the heat sink 20 is not in contact with at least part of the first cleavage region 2. The first cleavage region 2 will not affect the welding of the heat sink 20, nor will the heat sink 20 affect the coating of the first cleavage region 2. Figure 1 For example, the first cleavage region 2 is suspended on the heat sink 20 .

[0044] It should be noted that the length of the chip's light-emitting end face (the side with the first cleavage region 2) suspended above the heat sink 20 is generally 5 microns. When the length of the first cleavage region 2 is exactly 5 microns, the entire region is suspended. When the length of the first cleavage region 2 is greater than 5 microns, a portion of the region is suspended (the suspended length is 5 microns). When the length of the first cleavage region 2 is less than 5 microns, the entire region is suspended, and a portion of the main chip region 1 is also suspended, with the total suspended distance of the two being 5 microns.

[0045] Specifically, the laser chip forms the necessary resonant cavity structure of the laser by coating the front cavity with an anti-reflection film and the rear cavity with a high-reflection film, so that the photon energy can repeatedly oscillate and enhance in the resonant cavity structure, and emit laser after exceeding the threshold critical point. The high output power application of the laser forces the laser chip as the pump source to continuously improve its performance. The high-power laser output places increasing demands on the damage resistance of the front and rear cavities of the chip. The mainstream optimization method is to reserve a certain non-injection area outside the film layer near the front cavity, reduce the heat caused by current injection, and reduce the temperature tolerance of the film layer, thereby indirectly increasing the COMD threshold of the chip film layer to improve chip reliability.

[0046] The laser of this embodiment is designed to have different temperatures on the front and rear cavity surfaces. The front cavity surface has a higher temperature and higher heat dissipation requirements, which plays a decisive role in the COMD level of the device, thus forming an asymmetric structure device. When manufacturing the laser, the cleavage lines located on the front and rear bars are adjusted from the traditional evenly distributed in the middle to the side close to the first cleavage region 2 on the front cavity surface. Therefore, the cleavage region (i.e., the first cleavage region 2) retained on the front cavity surface that is not bonded to the heat sink is smaller, and the cleavage region (i.e., the second cleavage region 25) on the rear cavity surface that is bonded to the heat sink is larger, such as Figure 12 After cleavage into a single tube, the schematic diagram of the asymmetric structure is as follows Figure 1 See Figure 14 After cleavage, an HR film (high-reflection film 6) and an AR film (anti-reflection film 5) are deposited on the right side of the HR end cleavage region (i.e., the second cleavage region 25) and the left side of the AR end cleavage region (i.e., the first cleavage region 2), respectively. The coatings can be applied by vapor deposition, sputtering, etc. Specifically, an anti-reflection coating is formed on the AR surface 1-2 on the surface of the light-emitting mirror AR end cleavage region. Preferably, aluminum nitride layers (not shown) and aluminum oxide layers (not shown) are alternately deposited from the light-emitting mirror side. Preferably, a pair of aluminum nitride layers and aluminum oxide layers are formed, forming a total of two layers of anti-reflection coating. Alternatively, two pairs of aluminum nitride layers and aluminum oxide layers can be formed, forming a total of four layers of anti-reflection coating.

[0047] In some embodiments, a high reflective coating is formed on the cleaved region at the end of the light reflecting mirror HR, wherein, for example, silicon oxide layers (not shown) and titanium oxide layers (not shown) are alternately deposited, preferably so that a total of 12 layers (6 pairs) are deposited, i.e., 6 pairs of silicon oxide layers and titanium oxide layers are formed, for a total of 12 layers of high reflective coating. This structure is then soldered to a heat sink to obtain a structure such as Figure 1 The structure shown.

[0048] It should be noted that in this embodiment, the first cleave region 2 and the second cleave region 25 are located a certain distance apart at the AR and HR ends of the laser chip, respectively. These two regions are not covered with metal. When the laser chip is subsequently packaged on a heat sink, these two regions cannot be connected to the heat sink via metal for heat dissipation. However, the main chip region 1, located between the first cleave region 2 and the second cleave region 25, is covered with metal and adheres to the heat sink 20, thereby dissipating heat.

[0049] See also Figure 3 The first cleavage region 2 is suspended, and there is no heat sink 20 underneath for heat dissipation. The first cleavage region 2 is the light-emitting end. Due to energy concentration at the light-emitting end, the temperature of the first cleavage region 2 is higher than that of the second cleavage region 25. The suspended portion of the first cleavage region 2 has energy concentration and high temperature in the entire width W1 direction. The wider the width of the first cleavage region 2, the larger the location or proportion of the high temperature position, which will affect or increase the COMD threshold of the film layer of the chip. The second cleavage region 25 is a reflective surface, and the energy concentration and temperature are lower than the light-emitting surface. The bottom surface of the second cleavage region 25 is in contact with the heat sink, so the heat sink can dissipate heat for the second cleavage region 25. In addition, AR film generally uses an oxide film, which has poor heat dissipation. Moreover, AR film is a light-emitting surface, and high temperature will affect laser performance. HR surfaces 1-3 are reflective surfaces that are not prone to energy concentration and can dissipate heat through a heat sink.

[0050] The laser chip included in the laser of this embodiment forms an asymmetric cleavage region structure, which reduces the length of the first cleavage region 2 in the light-emitting direction, thereby reducing the volume of the first cleavage region 2, reducing the energy concentration in the first cleavage region 2, and reducing the temperature of the first cleavage region 2, thereby ensuring the performance of the laser and solving the problem of poor heat dissipation of the laser.

[0051] In the laser of this embodiment, see Figures 3 to 6 The heat sink 20 includes: a heat sink bonding surface 22, which is used to bond with the main chip area 1 and the second cleavage area 25; a heat sink target plane 23, which is the plane where the heat sink bonding surface 22 is located; wherein, the orthographic projection of the first cleavage area 2 on the heat sink target plane 23 is a first non-overlapping area 3; at least a part of the first non-overlapping area 3 does not overlap with the orthographic projection of the heat sink 20 on the heat sink target plane 23, and the orthographic projection of the second cleavage area 25 on the heat sink target plane 23 is a first overlapping area 4; the first overlapping area 4 overlaps with the orthographic projection of the heat sink 20 on the heat sink target plane 23.

[0052] Specifically, by determining whether the orthographic projections of the first cleavage region 2 and the second cleavage region 25 overlap with the heat sink 20 on the heat sink target plane 23, the size and position of the cleavage region can be precisely controlled during the production process, ensuring the stability and reproducibility of the laser chip 10 during mass production. Furthermore, by determining whether the orthographic projections of the first cleavage region 2 and the second cleavage region 25 overlap with the heat sink 20 on the heat sink target plane, heat dissipation management can be clearly optimized, ensuring that the light-emitting end face (i.e., the side coated with the AR film) does not become overheated due to contact with the heat sink, while the highly reflective end face (i.e., the side coated with the HR film) can fully dissipate heat. This also enhances structural stability, and by using a laser chip with an asymmetric cleavage region, the durability and reliability of the laser are improved.

[0053] Specifically, the laser chip after cleavage and lamination needs to be soldered to the heat sink 20 by soldering. Figure 13 The first cleavage region 2 and the AR film are not welded in a suspended manner on the heat sink 20. During the welding process, the liquid welding material will overflow, forming overflow solder 1-1 on the AR surface 1-2 and overflow solder 1-1 on the HR surface 1-3. The overflow solder 1-1 will cover the AR film and the HR film. Since the light-emitting end face coated with the AR film needs to emit light, the solder overflowing onto the AR film will block the light output and affect the overall performance of the laser.

[0054] In the laser of this embodiment, see Figures 6 to 8 The heat sink includes a heat sink normal plane 24; the heat sink normal plane 24 is perpendicular to the heat sink target plane; the heat sink normal plane 24 is perpendicular to the light output end face 21, and the length of the projection of the first non-overlapping area 3 on the heat sink normal plane 24 is a first non-overlapping length D1, and the length of the projection of the first overlapping area on the heat sink normal plane 24 is a first overlapping length D2; wherein, the first non-overlapping length D1 is equal to the first cleavage length, and the first overlapping length D2 is equal to the second cleavage length.

[0055] With the above-mentioned setting, the heat sink normal plane 24 is parallel to one side surface 26 of the laser chip 10, thereby saving materials and space, improving heat dissipation efficiency, and improving production efficiency. During specific production, the side surface of the heat sink 20 is interconnected with the structures of the first cleavage region 2 and the second cleavage region 25, thereby forming a laser chip 10 with uniform structure, which is conducive to forming a more uniform heat dissipation structure, thereby improving heat dissipation efficiency. In addition, the use of projection method for related length definition and related length comparison is mainly to optimize the structural design of the laser, ensure the controllability of heat dissipation, optical performance and manufacturing process, and its specific advantages and technical effects are as follows: First, unified scale, convenient for standardized design, the projection method eliminates the complexity of three-dimensional space, simplifies the geometric relationship into a plane projection, thereby facilitating accurate measurement and standardized calculation. In the actual production and quality inspection process, the use of the first non-overlapping length D1 and the first overlapping length D2 can avoid measurement errors caused by angle changes, making the structural parameters of the laser chip and the heat sink more consistent. Second, ensure efficient heat dissipation from the heat sink, improving laser reliability: The first cleavage region (AR end) does not overlap with the heat sink to prevent uneven heat dissipation. Since the first cleavage region (AR end) is the light-emitting end and its temperature is higher than the HR end, direct attachment to the heat sink will cause heat accumulation, hindering heat dissipation. Therefore, ensuring that the projection of the first cleavage region on the heat sink target plane does not overlap helps reduce local hot spots and improve the reliability of the optical film (AR film). The second cleavage region (HR end) overlaps with the heat sink to improve heat dissipation efficiency. The second cleavage region (HR end) reflects light and concentrates less energy, but still generates heat. Therefore, the design ensures that the projection of the second cleavage region on the heat sink target plane overlaps, allowing it to directly attach to the heat sink, effectively transferring heat and improving heat dissipation efficiency. By projecting the overlapping area, the heat dissipation capacity of the HR end can be accurately calculated, ensuring that the design meets the requirements for long-term stable laser operation.

[0056] Specifically, the laser chip after cleavage and lamination needs to be soldered to the heat sink 20 by soldering. Figure 13 The first cleavage region 2 and the AR film are not welded in a suspended manner on the heat sink 20. During the welding process, the liquid welding material will overflow, forming the overflow solder 1-1 of the AR surface 1-2 and the overflow solder 1-1 of the HR surface 1-3. The overflow solder 1-1 will cover the front end surface of the AR film and the rear end surface of the HR surface 1-3. Since the front end surface of the AR film needs to emit light, the solder overflowing to the front end surface of the AR film will block the light output and affect the overall performance. Therefore, it is necessary to set Figure 14 In the suspended state, the AR surface 1-2 will not be affected by the overflow solder 1-1, that is, the light output will not be affected.

[0057] See also Figure 3The first cleavage region 2 is suspended on the upper side of the heat sink 20, and there is no heat sink 20 below for heat dissipation. The first cleavage region 2 is the light-emitting end. Due to energy concentration on the light-emitting surface, the temperature of the first cleavage region 2 is higher than that of the second cleavage region 25. The suspended portion of the first cleavage region 2 has energy concentration and high temperature in the entire width W1 direction. The wider the width of the first cleavage region 2, the larger the area or proportion of the high temperature position, which affects or increases the COMD threshold of the chip's film layer. The second cleavage region 25 is a reflective surface, and its energy concentration and temperature are lower than those of the light-emitting surface. The bottom surface of the second cleavage region 25 is in contact with the heat sink, so the heat sink can dissipate heat from the second cleavage region 25. In addition, the AR film is an oxide film with poor heat dissipation. Since the AR film is a light-emitting surface, high temperature will affect laser performance. The HR surfaces 1-3 are reflective surfaces, where energy concentration does not occur and heat can be dissipated by the heat sink.

[0058] The laser of this embodiment forms an asymmetric cleavage region structure, which reduces the length of the first cleavage region 2 in the light-emitting direction, thereby reducing the volume of the first cleavage region 2, reducing the energy concentration in the first cleavage region 2, and reducing the temperature of the first cleavage region 2, thereby ensuring the performance of the laser and solving the problem of poor heat dissipation of the laser.

[0059] In the laser of this embodiment, the ratio of the first non-overlapping length D1 to the first overlapping length D2 is less than or equal to 3 / 17.

[0060] By adopting the above-mentioned setting and setting the first cleavage region 2 and the second cleavage region 25 according to the above-mentioned standards, it is possible to better balance the production cost and the heat dissipation efficiency.

[0061] In the laser of this embodiment, the laser chip 10 further includes an anti-reflection film 5 and a high-reflection film 6. In the light-emitting direction, the anti-reflection film 5 is adjacent to the first cleavage region 2, and in the opposite direction to the light-emitting direction, the high-reflection film 6 is adjacent to the second cleavage region 25. Along the light-emitting direction of the laser, the length of the anti-reflection film 5 is a first anti-reflection length, and the length of the high-reflection film 6 is a first high-reflection length; wherein, the first anti-reflection length is less than the first high-reflection length.

[0062] With the above configuration, the first antireflection length is set to be smaller than the first high reflection length. When the chip is soldered to the heat sink 20, the solder will not directly contact the antireflection film 5, thereby improving the protective effect of the antireflection film 5 and ensuring the normal operation of the laser.

[0063] In the laser of this embodiment, see Figure 10 、 Figure 11The orthographic projection of the antireflection film 5 on the heat sink target plane 23 does not overlap with the orthographic projection of the heat sink 20 on the heat sink target plane 23; the orthographic projection of the high-reflection film 6 on the heat sink target plane 23 overlaps with the orthographic projection of the heat sink 20 on the heat sink target plane 23.

[0064] Specifically, the optical film layer is not only coated on the cavity surface of the laser chip, but also on the metal electrodes on the front and back of the laser chip, forming an optical film flip film. Therefore, there are several problems: Figure 1 As shown, the adhesion between the optical film and the front and back metal electrodes of the laser chip is poor, which causes the optical film layer to easily fall off to the cavity surface of the laser chip, causing debris contamination to the cavity surface; when the optical film falls off, the edge connection of the optical film formed by the film and the cavity surface is torn, causing the edge of the optical film on the cavity surface to be damaged, affecting the quality of the optical film on the cavity surface; the optical film is formed on the front and back metal electrodes of the laser chip, and when the laser chip is packaged and mounted, it can block the solder and prevent the solder from overflowing to the cavity surface of the laser chip and causing damage to the cavity surface; after the optical film falls off, it loses its blocking effect on the solder.

[0065] See also Figure 10 、 Figure 11 In the laser of this embodiment, the orthographic projection of the antireflection film 5 on the heat sink target plane 23 is a second non-overlapping area 7, and the area where the orthographic projection of the high-reflection film 6 on the heat sink target plane 23 overlaps with the orthographic projection of the heat sink 20 on the heat sink target plane 23 is a second overlapping area 8; the projection length of the second non-overlapping area 7 on the heat sink normal plane 24 is the second non-overlapping length D3, and the projection length of the second overlapping area 8 on the heat sink normal plane 24 is the second overlapping length D4; wherein, the second non-overlapping length D3 is equal to the first antireflection length, and the second overlapping length D4 is equal to the first high-reflection length.

[0066] With the above arrangement, the sizes of the antireflection film 5 and the high reflective film 6 are set according to the side surface 26 of the heat sink, which is conducive to forming a more uniform heat dissipation structure, thereby improving heat dissipation efficiency and saving material and production costs.

[0067] In the laser of this embodiment, the ratio of the second non-overlapping length D3 to the second overlapping length D4 ranges from 0.1 to 0.2.

[0068] The above arrangement ensures the light transmission and reflection effects of the anti-reflection film 5 and the high-reflection film 6 while reducing the production difficulty, saving materials and lowering the production cost.

[0069] In the laser of this embodiment, the sum of the first non-overlapping length D1 and the second non-overlapping length D3 is the third non-overlapping length, and the sum of the first overlapping length D2 and the second overlapping length D4 is the third overlapping length, wherein the ratio of the third overlapping length to the third non-overlapping length ranges from 5 to 10.

[0070] In the laser of this embodiment, the anti-reflection film 5 also includes a first anti-reflection surface 51, which is a surface away from the first cleavage region 2 along the light-emitting direction, and the first anti-reflection surface 51 has a first anti-reflection temperature; the high-reflection film 6 also includes a first high-reflection surface 61, which is a surface away from the second cleavage region 25 along the light-emitting direction, and the first high-reflection surface 61 has a first high-reflection temperature; wherein, when the laser emits light, the difference between the first anti-reflection temperature and the first high-reflection temperature is less than 45°C.

[0071] With the above configuration, when the laser is operating, if the temperature difference between the first antireflection surface 51 and the first high-reflection surface 61 is too large, it indicates that the temperature of the first antireflection surface 51 is too high. In this case, the first cleavage length can be further reduced to ensure smooth operation of the laser. If the temperature difference between the first antireflection surface 51 and the first high-reflection surface 61 is not large, it means that the requirements are met.

[0072] The wafer of this embodiment, see Figure 12 , including multiple laser chips 10, the wafer is used to manufacture laser chips 10, at least two laser chips 10 are cleaved from the wafer; the first cleavage region 2 of one of the two adjacent laser chips 10 on the wafer is connected to the second cleavage region 25 of the other of the two adjacent laser chips 10.

[0073] A wafer of this embodiment includes a plurality of laser chips 10, each laser chip 10 including a main chip region, a first cleavage region, and a second cleavage region; for each laser chip: the first cleavage region is adjacent to the main chip region, and the first cleavage region has a light-emitting end face for emitting light; the second cleavage region is adjacent to an end of the main chip region away from the first cleavage region; the first cleavage region has a first cleavage length, and the second cleavage region has a second cleavage length; the first cleavage length and the second cleavage length are the lengths of the first cleavage region and the second cleavage region, respectively, along the light-emitting direction of the laser; the first cleavage length is less than the second cleavage length. The wafer is used to manufacture laser chips, and at least two laser chips are cleaved from the wafer; the first cleavage region of one of the two adjacent laser chips on the wafer is connected to the second cleavage region of the other of the two adjacent laser chips.

[0074] Optionally, for the multiple laser chips cleaved from the wafer, the length of each first cleavage region of the multiple laser chips is equal, and the length of each second cleavage region of the multiple laser chips is equal.

[0075] See also Figure 12 In the wafer of this embodiment, at least two laser chips are arranged in sequence to form a bar. There are at least two bars. The lasers in one of two adjacent bars correspond to the lasers in the other bar. A cleave mark 30 is provided between the two adjacent bars. The cleave mark 30 separates the first cleave region 2 of the laser in one bar from the second cleave region 25 of the laser in the other bar. This arrangement facilitates the manufacture of laser chips 10 with an asymmetric structure, thereby improving production efficiency.

[0076] Specifically, the lengths of the first cleavage region 2 and the second cleavage region 25 along the light emitting direction of the laser are adjusted by adjusting the cleavage mark 30 .

[0077] Figure 12 and Figure 15 The distribution of chips on the wafer is shown in Figure 2. For simplicity, only two adjacent bars are placed. Figure 15 As shown, a cleavage area is reserved on the front cavity surface of the front Bar and the back cavity surface of the back Bar, which is generally not plated with metal. At the same time, a cleavage mark 30 is photoetched in the middle of the cleavage area. Along the middle cleavage mark 30, the wafer is cleaved into independent Bar devices using a scribing and splitting process, and placed in the PECVD in the form of stacked Bars for vacuum coating. The conventional design is to reserve unplated cleavage areas of the same distance at AR and HR. Then, since this part is not plated with metal, it cannot be directly connected to the heat sink 20 for heat dissipation, which will inevitably lead to an increase in the near-cavity surface temperature, reduce its COMD level, and thus reduce reliability. The laser of this embodiment has different temperatures on the front and rear cavity surfaces. The temperature of the front cavity surface is higher, and the heat dissipation requirements are also higher, which plays a decisive role in the COMD level of the device. The present invention is as follows Figure 12 As shown in the figure, an asymmetric device structure was designed. During laser manufacturing, the cleavage lines located on the front and rear bars were adjusted from the traditional evenly distributed center to one side closer to the front cavity surface. As a result, the unmetallized cleavage area (i.e., the first cleavage area 2) on the front cavity surface is reduced, while the rear cavity surface retains more non-metallic (i.e., the second cleavage area 25), thereby optimizing the structure of the cleavage area and improving heat dissipation efficiency.

[0078] A laser chip can be used to manufacture the above-mentioned laser. The laser chip includes a main chip area 1, a first cleavage area 2, and a second cleavage area 25. The first cleavage area 2 is adjacent to the main chip area 1, and the first cleavage area 2 has an output end face for light output. The second cleavage area 25 is adjacent to one end of the main chip area 1 far from the first cleavage area 2. Along the light output direction of the laser chip, the length of the first cleavage area 2 is the first cleavage length, and the length of the second cleavage area 25 is the second cleavage length. The first cleavage length is less than the second cleavage length. Among them, the laser chip includes a bar or a single tube.

[0079] By using the above-mentioned laser chip 10, a laser with an asymmetrically structured cleavage area can be manufactured, thereby reducing the heat accumulation on the light output surface and improving the overall performance of the laser. Embodiment

[0080] See Figure 3 , the length of the first cleavage area 2 in the light output direction of the laser is W1; the length of the second cleavage area 25 in the light output direction of the laser is W2. Among them, W1 + W2 < 100 μm, and W1 < W2. During specific production, while forming an asymmetric cleavage area, ensure that the total length of the cleavage area is less than 100 μm. In this way, the space of the wafer can be saved and the productivity can be improved.

[0081] In addition, for Embodiment 1, there is the following Comparative Example 1: W1 + W2 ≥ 100 μm (comparative group). The problems of this Comparative Example 1 are: First, it wastes the wafer space and reduces the number of chips that can be produced per unit wafer. Second, the heat dissipation path becomes longer, which may cause local overheating and affect the reliability. Third, the device packaging size increases, affecting the packaging efficiency. As a result, the productivity is reduced and the number of chips per wafer is decreased. And the local temperature rises, and the reliability of the laser decreases.

[0082] Through Embodiment 1 and the comparative example, it can be obtained that when W1 + W2 < 100 μm, the productivity is improved. The shorter cleavage area allows more chips to be manufactured on the same wafer. It improves heat dissipation, shortens the heat path, enables heat energy to be conducted to the heat sink faster, and improves the heat dissipation efficiency. It optimizes the packaging structure, reduces the ineffective space, and improves the overall efficiency. The setting of W1 + W2 < 100 μm takes into account the manufacturing cost, heat dissipation, and packaging efficiency, and is the best choice. Embodiment

[0083] See Figure 3 , the length W1 of the first cleavage area 2 in the light output direction of the laser is < 10 μm. In this way, it can be ensured that the length of the first cleavage area 2 is within a standard value, thereby reducing the heat generation.

[0084] In addition, for the first embodiment, there is a comparative example 2 as follows: W1 ≥ 10 μm (comparative group). The problems of this comparative example 2 are as follows: First, the temperature at the AR end is too high, and the optical film layer (AR film) is easily damaged, reducing its lifespan. Second, local energy aggregation is severe, resulting in a decrease in the COMD threshold. That is to say, the optical loss of this comparative example 2 increases, and the laser output efficiency decreases. The reliability is reduced, and the film layer at the AR end may be damaged after long-term operation.

[0085] From the first embodiment and the comparative examples, it can be concluded that the advantages of W1 < 10 μm are as follows: First, reduce the temperature accumulation at the AR end and improve the lifespan of the laser. Second, increase the COMD threshold of the laser to ensure high-power output. Therefore, W1 < 10 μm can effectively reduce the temperature, optimize the performance of the optical film layer, and is the optimal parameter. Embodiment

[0086] See <000,0226>, the value range of the first antireflection length L1 is 0.05 μm < L1 < 0.5 μm. Within this width range, while ensuring the light transmission function of the antireflection film 5, the antireflection film 5 can be firmly plated on the first cleavage region 2. Embodiment

[0087] See Figure 3 , the value range of the first high-reflection length L2 is 0.5 μm < L2 < 2.5 μm. Within this width range, while ensuring the light transmission function of the high-reflection film ⑥, the high-reflection film 6 can be firmly plated on the second cleavage region 25 and is not prone to film turning, ensuring the performance of the laser. [[ID=]18]

[0088] It should be noted that the terms "first", "second", etc. in the description, claims, and above-mentioned drawings of this application are used to distinguish similar objects and do not necessarily describe a specific order or sequence. It should be understood that such used data can be interchanged under appropriate circumstances so that the embodiments of this application described here can be implemented in an order different from those illustrated or described here. In addition, the terms "comprising" and "having" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or device that includes a series of steps or units does not necessarily have to be limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or are inherent to these processes, methods, products, or devices.

[0089] Optionally, the specific examples in this embodiment can refer to the examples described in the above embodiments, and will not be elaborated here.

[0090] The serial numbers of the above embodiments of this application are only for description and do not represent the advantages or disadvantages of the embodiments.

[0091] In the above embodiments of the present application, the description of each embodiment has its own focus. For parts that are not described in detail in a certain embodiment, please refer to the relevant description of other embodiments.

[0092] The above is only a preferred embodiment of the present application. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present application. These improvements and modifications should also be regarded as the scope of protection of the present application.

Claims

1. A laser, characterized in that: include: A laser chip and a heat sink, wherein the laser chip includes a main chip area, a first cleavage area, and a second cleavage area; The first cleavage region is adjacent to the main chip region, and the first cleavage region has a light emitting end face for emitting light; The second cleavage region is adjacent to an end of the main chip region away from the first cleavage region; Along the light emitting direction of the laser, the length of the first cleavage region is a first cleavage length, and the length of the second cleavage region is a second cleavage length; the first cleavage length is smaller than the second cleavage length; A heat sink is provided, wherein the heat sink is at least in contact with the main chip region; and the heat sink is spaced apart from at least a portion of the first cleavage region.

2. The laser according to claim 1, characterized in that The heat sink comprises: a heat sink bonding surface, the heat sink bonding surface being used to bond with the main chip region and the second cleavage region; Among them, the plane where the heat sink bonding surface is located is the heat sink target plane; the orthographic projection of the first cleavage zone on the heat sink target plane is a first non-overlapping area; at least part of the first non-overlapping area does not overlap with the orthographic projection of the heat sink on the heat sink target plane, and the orthographic projection of the second cleavage zone on the heat sink target plane is a first overlapping area; the first overlapping area overlaps with the orthographic projection of the heat sink on the heat sink target plane.

3. The laser according to claim 2, characterized in that The heat sink includes a heat sink normal plane; the heat sink normal plane is perpendicular to the heat sink target plane; the heat sink normal plane is perpendicular to the light output end face, the length of the projection of the first non-overlapping area on the heat sink normal plane is a first non-overlapping length D1, and the length of the projection of the first overlapping area on the heat sink normal plane is a first overlapping length D2; The first non-overlapping length D1 is equal to the first cleavage length, and the first overlapping length D2 is equal to the second cleavage length.

4. The laser according to claim 3, characterized in that A ratio of the first non-overlapping length D1 to the first overlapping length D2 is less than or equal to 3 / 17.

5. The laser according to claim 4, characterized in that The laser chip further includes an anti-reflection film and a high-reflection film; in the light-emitting direction, the anti-reflection film is adjacent to the first cleavage region, and in the direction opposite to the light-emitting direction, the high-reflection film is adjacent to the second cleavage region; along the light-emitting direction of the laser, the length of the anti-reflection film is a first anti-reflection length, and the length of the high-reflection film is a first high-reflection length; Wherein, the first anti-reflection length is shorter than the first high-reflection length.

6. The laser according to claim 5, characterized in that The orthographic projection of the antireflection film on the heat sink target plane does not overlap with the orthographic projection of the heat sink on the heat sink target plane; the orthographic projection of the high reflection film on the heat sink target plane overlaps with the orthographic projection of the heat sink on the heat sink target plane.

7. The laser according to claim 6, characterized in that The orthographic projection of the antireflection film on the heat sink target plane is a second non-overlapping area, and the area where the orthographic projection of the high-reflection film on the heat sink target plane overlaps with the orthographic projection of the heat sink on the heat sink target plane is a second overlapping area; the projection length of the second non-overlapping area on the heat sink normal plane is a second non-overlapping length D3, and the projection length of the second overlapping area on the heat sink normal plane is a second overlapping length D4; The second non-overlapping length D3 is equal to the first anti-reflection length, and the second overlapping length D4 is equal to the first high-reflection length.

8. The laser according to claim 7, characterized in that The ratio of the second non-overlapping length D3 to the second overlapping length D4 ranges from 0.1 to 0.

2.

9. The laser according to claim 8, characterized in that The sum of the first non-overlapping length D1 and the second non-overlapping length D3 is a third non-overlapping length, and the sum of the first overlapping length D2 and the second overlapping length D4 is a third overlapping length, wherein the ratio of the third overlapping length to the third non-overlapping length ranges from 5 to 10.

10. The laser according to claim 9, characterized in that The antireflection film further includes a first antireflection surface, the first antireflection surface is a surface away from the first cleavage region along the light emitting direction, and the first antireflection surface has a first antireflection temperature; The high-reflection film further includes a first high-reflection surface, the first high-reflection surface is a surface away from the second cleavage region along the light emitting direction, and the first high-reflection surface has a first high-reflection temperature; Wherein, when the laser emits light, the difference between the first anti-reflection temperature and the first high-reflection temperature is less than 45°C.

11. A wafer comprising a plurality of laser chips, wherein the wafer is used to manufacture the laser chips in the laser according to any one of claims 1 to 10, characterized in that: At least two laser chips are cleaved from the wafer; a first cleavage region of one of the two adjacent laser chips on the wafer is connected to a second cleavage region of the other laser chip.

12. A laser chip, characterized in that: The laser chip includes a main chip region, a first cleavage region, and a second cleavage region; the first cleavage region is adjacent to the main chip region, and the first cleavage region has a light-emitting end face for emitting light; the second cleavage region is adjacent to an end of the main chip region away from the first cleavage region; along the light-emitting direction of the laser chip, the length of the first cleavage region is a first cleavage length, and the length of the second cleavage region is a second cleavage length; the first cleavage length is smaller than the second cleavage length; Wherein, the laser chip includes a single tube or a bar.

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