Multi-chip laser array bonding apparatus and method

Abstract

The disclosure provides a multi-chip laser array welding device and method, and relates to the technical field of semiconductor lasers. The device comprises a base for placing a laser array to be welded; a front end positioning block for positioning the laser array to be welded from one end; a rear end positioning block for positioning the laser array to be welded from the other end in cooperation with the front end positioning block; side blocking positioning blocks for positioning the laser array to be welded from both sides; and an array pressing block for positioning the laser array to be welded from the top end. The laser array to be welded comprises alternating semiconductor laser chips and tungsten-copper heat sinks. Gold-tin alloy pads are arranged on the top ends of the semiconductor laser chips and the tungsten-copper heat sinks. Aluminum nitride ceramics and zirconium oxide ceramics are alternately arranged on the top ends of the gold-tin alloy pads. The number and placement of the aluminum nitride ceramics correspond to the number and placement of the tungsten-copper heat sinks. The welding surface of the aluminum nitride ceramics is configured as a metal layer, and the non-welding surface is configured as an insulating layer.

Description

Technical Field

[0001] This disclosure relates to the field of semiconductor laser technology, and more specifically, to a multi-chip laser array welding apparatus and method. Background Technology

[0002] Semiconductor laser arrays can achieve chip center-to-center spacing of ≤1mm, and the number of chips can be expanded, resulting in a small array size and high peak power density. Packaging such arrays is challenging, primarily due to the large number of chips (generally ≥3). To reduce the number and time of high-temperature soldering, it is desirable to sinter all chips in the array into a single unit at once. In this case, sintering conditions must first be set and optimized to ensure successful soldering of all chips in one go. Simultaneously, it is crucial to ensure no voids are formed between each chip and the heat sink, as soldering voids will cause stress on the chip, affecting heat dissipation and reducing performance and lifespan. Furthermore, due to the large number of chips in the array, the consistency of the cavity surfaces of all chips must be ensured during soldering to further control the beam directivity of the entire array. Therefore, for high-power semiconductor laser arrays, the more chips there are, the greater the difficulty of the soldering process. Additionally, traditional soldering processes using a combination of soft and hard solders present challenges. While soft solders have better ductility and are fine for short-term operation, they are prone to fatigue failure under prolonged high-temperature conditions, accelerating chip degradation and reducing chip lifespan.

[0003] In realizing the concept disclosed herein, the inventors discovered at least the following problems in the related technologies: repeated high-temperature welding can cause certain damage to semiconductor laser chips; soft solder is prone to fatigue when working under high-temperature conditions for a long time, which accelerates chip degradation and reduces chip lifespan; and it is quite difficult to control the overall neatness of the array and the consistency of the chip cavity surface when forming an array of multi-chip integrated high-temperature sintering at one time. Summary of the Invention

[0004] In view of this, the present disclosure provides a multi-chip laser array welding apparatus and method.

[0005] One aspect of this disclosure provides a multi-chip laser array welding apparatus, comprising: a base for placing a laser array to be welded; a front positioning block disposed at one end of the base for positioning the laser array to be welded from one end; a rear positioning block movably disposed at the other end of the base for cooperating with the front positioning block to position the laser array to be welded from the other end; side positioning blocks disposed on both sides of the base for positioning the laser array to be welded from both sides; and an array pressing block disposed at the upper end of the laser array to be welded for positioning the laser array to be welded from the upper end. The laser array to be welded includes alternately arranged semiconductor laser chips and tungsten copper heat sinks, with gold-tin solder layers on the welding surfaces of the tungsten copper heat sinks and semiconductor laser chips; gold-tin alloy solder sheets are laid on the upper ends of the semiconductor laser chips and tungsten copper heat sinks, with aluminum nitride ceramics and zirconium oxide ceramics alternately arranged on the upper ends of the gold-tin alloy solder sheets, the number and placement of the aluminum nitride ceramics corresponding one-to-one with the number and placement of the tungsten copper heat sinks, the welding surface of the aluminum nitride ceramics being configured as a metal layer, and the non-welding surface being configured as an insulating layer.

[0006] According to an embodiment of this disclosure, the side of the base used to hold the laser array to be welded is tilted at a preset angle.

[0007] According to an embodiment of this disclosure, the device further includes: a chip front cavity positioning ceramic disposed on a base; wherein, the rear positioning block is provided with a groove adapted to the chip front cavity positioning ceramic, so that the rear positioning block can slide along the chip front cavity positioning ceramic.

[0008] According to embodiments of this disclosure, the chip front cavity positioning ceramic is configured as an insulator, and its surface is pre-mirror polished.

[0009] According to an embodiment of this disclosure, an arc-shaped protrusion is provided at the end of the rear positioning block that contacts the laser array to be welded; wherein, the arc-shaped protrusion contacts one side of the tungsten copper heat sink during positioning.

[0010] According to an embodiment of this disclosure, the device further includes: a side positioning ceramic disposed between the side blocking positioning block and the laser array to be welded, for maintaining the alignment of the laser array to be welded under the positioning action of the side blocking positioning block; wherein the surface of the side positioning ceramic is configured as an insulator.

[0011] According to an embodiment of this disclosure, the device further includes: a rear slider disposed on the rear positioning block, which is capable of sliding together with the rear positioning block; wherein the rear slider contacts one side of the aluminum nitride ceramic during positioning.

[0012] According to embodiments of this disclosure, the base, front positioning block, rear positioning block, side blocking positioning block, array pressure block, and rear slider are all made of tungsten copper material with a low coefficient of thermal expansion.

[0013] According to embodiments of this disclosure, the coefficient of thermal expansion of aluminum nitride ceramic is 5.6 × 10⁻⁶. -6 At ℃, the coefficient of thermal expansion of zirconia ceramic is 10.5 × 10⁻⁶. -6 / ℃.

[0014] Another aspect of this disclosure provides a method for welding a multi-chip laser array, comprising: acquiring a laser array to be welded; placing the laser array to be welded at a preset position of a multi-chip laser array welding device; using the multi-chip laser array welding device to position the laser array to be welded; welding the positioned laser array to be welded, wherein the gold-tin alloy solder sheet becomes molten at high temperature and flows to the metal layer, and automatically breaks off at the location without the metal layer, completing the welding between the semiconductor laser chip and the tungsten copper heat sink, and between the tungsten copper heat sink and the aluminum nitride ceramic; and removing the zirconium oxide ceramic after condensation to obtain the welded multi-chip laser array.

[0015] Compared with the prior art, the multi-chip laser array welding apparatus and method provided in this disclosure have at least the following advantages:

[0016] (1) The multi-chip laser array welding apparatus and method provided in this disclosure pre-arranges multiple semiconductor laser chips and tungsten copper heat sinks alternately to form an assembly, then lays a whole sheet of gold-tin alloy (AuSn) solder on the top of the assembly, and further alternately places aluminum nitride ceramics and zirconium oxide ceramics on the AuSn solder to form a laser array to be welded. Finally, the laser array to be welded is precisely positioned, so that multiple semiconductor laser chips and semiconductor laser chips and independent insulating ceramics can be integrated and welded in one high temperature, avoiding the damage to the chips caused by multiple high temperature welding. At the same time, hard solder is used on the welding surface, avoiding the chip degradation caused by fatigue due to long-term high temperature operation of soft solder, and improving the service life of the chip.

[0017] (2) The multi-chip laser array welding apparatus and method provided in this disclosure can effectively release the stress caused to the chip by the all-hard solder welding through discrete aluminum nitride ceramic welding, thereby further improving the service life of the semiconductor laser.

[0018] (3) The multi-chip laser array welding apparatus and method provided in this disclosure uses tungsten copper material with a low coefficient of thermal expansion, which can not only avoid the problem of excessive stress caused by the large coefficient of thermal expansion of the material during the welding process, thereby improving the welding quality, but also realize the precise positioning of multiple laser chips, heat sinks and discrete aluminum nitride ceramics, further realizing high-precision integrated welding of multi-chip laser arrays. Attached Figure Description

[0019] The above and other objects, features and advantages of this disclosure will become clearer from the following description of embodiments with reference to the accompanying drawings, in which:

[0020] Figure 1 A schematic diagram of a multi-chip laser array welding apparatus according to an embodiment of the present disclosure is shown.

[0021] Figure 2 A schematic diagram illustrating the structure of a laser array to be welded according to an embodiment of the present disclosure is shown.

[0022] Figure 3 A schematic diagram of a laser array welded according to an embodiment of the present disclosure is shown.

[0023] [Attached image labels]

[0024] 1-Base;

[0025] 2-Front-end positioning block;

[0026] 3-Backend positioning block;

[0027] 4-Side guard positioning block;

[0028] 5-Array pressing blocks;

[0029] 6-Chip front cavity positioning ceramic;

[0030] 7-Side positioning ceramic;

[0031] 8- Rear end slider;

[0032] 9-Laser array to be welded; 91-Semiconductor laser chip; 92-Tungsten copper heat sink; 93-AuSn solder pad; 94-Aluminum nitride ceramic; 95-Zirconium oxide ceramic;

[0033] 10 - Laser array after welding. Detailed Implementation

[0034] The embodiments of the present disclosure will now be described with reference to the accompanying drawings. However, it should be understood that these descriptions are exemplary only and are not intended to limit the scope of the disclosure. In the following detailed description, numerous specific details are set forth to provide a thorough understanding of the embodiments of the present disclosure for ease of explanation. However, it will be apparent that one or more embodiments may be practiced without these specific details. Furthermore, descriptions of well-known structures and techniques are omitted in the following description to avoid unnecessarily obscuring the concepts of the present disclosure.

[0035] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit this disclosure. The terms “comprising,” “including,” etc., as used herein indicate the presence of the stated features, steps, operations, and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, or components.

[0036] All terms used herein (including technical and scientific terms) have the meanings commonly understood by those skilled in the art, unless otherwise defined. It should be noted that the terms used herein are to be interpreted in a manner consistent with the context of this specification, and not in an idealized or overly rigid way.

[0037] When using expressions such as "at least one of A, B and C", they should generally be interpreted in accordance with the meaning that is commonly understood by those skilled in the art (e.g., "a system having at least one of A, B and C" should include, but is not limited to, a system having A alone, a system having B alone, a system having C alone, a system having A and B, a system having A and C, a system having B and C, and / or a system having A, B and C, etc.).

[0038] Semiconductor laser arrays can achieve chip center-to-center spacing of ≤1mm, and the number of chips can be expanded, resulting in a small array size and high peak power density. Packaging such arrays is quite challenging, primarily due to the large number of chips (generally ≥3). To reduce the number of high-temperature soldering processes and the time spent on each chip, it is desirable to sinter all chips in the array into a single unit at once. In this case, the sintering conditions must first be set and optimized to ensure successful soldering of all chips in one go. Simultaneously, it is crucial to ensure that no voids are formed between each chip and the heat sink, as soldering voids will cause stress on the chip, affecting heat dissipation and reducing performance and lifespan. Furthermore, due to the large number of chips in the array, the consistency of the cavity surfaces of all chips must be ensured during soldering to further control the beam directivity of the entire array after packaging. Therefore, for high-power semiconductor laser arrays, the more chips there are, the greater the difficulty of the soldering process. Additionally, traditional soldering processes using a combination of soft and hard solders present challenges. While soft solders have better ductility and are fine for short-term operation, they are prone to fatigue failure under prolonged high-temperature conditions, accelerating chip degradation and reducing chip lifespan.

[0039] In realizing the concept disclosed herein, the inventors discovered at least the following problems in the related technologies: repeated high-temperature welding can cause certain damage to semiconductor laser arrays; soft solder is prone to fatigue when working under high-temperature conditions for a long time, which accelerates chip degradation and reduces chip lifespan; and it is quite difficult to control the overall neatness of the array and the consistency of the chip cavity surface when the multi-chip integrated array is formed by one-time high-temperature sintering.

[0040] Based on this, the present disclosure provides a multi-chip laser array welding apparatus to solve the technical problems of the prior art, which requires multiple high-temperature welding processes that can damage the chip, and the easy fatigue failure of soft solder that leads to chip degradation and short service life.

[0041] The device includes: a base for placing the laser array to be welded; a front positioning block located at one end of the base for positioning the laser array to be welded from one end; a rear positioning block movably located at the other end of the base for cooperating with the front positioning block to position the laser array to be welded from the other end; side positioning blocks located on both sides of the base for positioning the laser array to be welded from both sides; and an array pressing block located at the top of the laser array to be welded for positioning the laser array to be welded from the top. The laser array to be welded includes alternating semiconductor laser chips and tungsten-copper heat sinks. The welding surfaces of the tungsten-copper heat sinks and semiconductor laser chips are provided with gold-tin solder layers. Gold-tin alloy solder sheets are laid on the upper ends of the semiconductor laser chips and tungsten-copper heat sinks. Alkali nitride ceramics and zirconium oxide ceramics are alternately arranged on the upper ends of the gold-tin alloy solder sheets. The number and placement of the aluminum nitride ceramics correspond one-to-one with the number and placement of the tungsten-copper heat sinks. The welding surface of the aluminum nitride ceramics is configured as a metal layer, and the non-welding surface is configured as an insulating layer.

[0042] The multi-chip laser array welding apparatus provided in this disclosure pre-arranges multiple semiconductor laser chips and tungsten-copper heat sinks alternately to form an assembly. Then, a single sheet of gold-tin alloy (AuSn) solder is laid on top of this assembly. Further, aluminum nitride ceramics and zirconium oxide ceramics are alternately placed on the AuSn solder sheet to form the laser array to be welded. Finally, the laser array is precisely positioned, enabling integrated welding of multiple semiconductor laser chips, as well as between semiconductor laser chips and individual insulating ceramics, through a single high-temperature process. This avoids the damage to the chips caused by multiple high-temperature welding processes. Simultaneously, hard solder is used on all welding surfaces, avoiding the chip degradation defects caused by fatigue due to prolonged high-temperature operation of soft solder, thus extending the chip's lifespan.

[0043] To make the objectives, technical solutions, and advantages of this disclosure clearer, the following detailed description is provided in conjunction with specific embodiments and the accompanying drawings.

[0044] Figure 1 A schematic diagram of a multi-chip laser array welding apparatus according to an embodiment of the present disclosure is shown.

[0045] like Figure 1 As shown, the multi-chip laser array welding device of this embodiment may include: a base 1, a front positioning block 2, a rear positioning block 3, a side blocking positioning block 4, and an array pressing block 5.

[0046] The base 1 is used to place the laser array 9 to be welded.

[0047] In this embodiment, the laser array 9 to be welded includes alternating semiconductor laser chips 91 and tungsten copper heat sinks 92, wherein the welding surfaces of the tungsten copper heat sink 92 and the semiconductor laser chips 91 are pre-formed with a gold-tin solder layer.

[0048] A whole piece of AuSn solder sheet 93 is laid on the upper end of the semiconductor laser chip 91 and the tungsten copper heat sink 92. Aluminum nitride ceramic 94 and zirconia ceramic 95 are alternately arranged on the upper end of the AuSn solder sheet 93. The number and placement of aluminum nitride ceramic 94 correspond one-to-one with the number and placement of tungsten copper heat sink 92 (the zirconia ceramic 95 is placed between the aluminum nitride ceramic 94 to position the aluminum nitride ceramic 94 and ensure that the aluminum nitride ceramic 94 and the tungsten copper heat sink 92 are positioned accordingly).

[0049] The welded surfaces of aluminum nitride ceramic 94 are configured as metal layers, and the non-welded surfaces are configured as insulating layers. In addition, all surfaces of zirconia ceramic 95 are configured as insulating layers.

[0050] In this embodiment, the base 1 can be designed with an inclination angle, that is, the side of the base 1 used to place the laser array 9 to be welded is tilted at a preset angle, so that the parts placed on it can obtain the fixing force generated by the gravity component.

[0051] The front positioning block 2 is located at one end of the base 1 and is used to position the laser array 9 to be welded from one end.

[0052] In this embodiment, the front positioning block 2 has a groove, which can be fixed to the front end of the base 1 by screws, for example, to position the laser array 9 to be welded from the front end.

[0053] The rear positioning block 3 is movably located at the other end of the base 1, and is used to cooperate with the front positioning block 2 to position the laser array 9 to be welded from the other end.

[0054] In this embodiment, the rear positioning block 3 can be movably disposed at the rear end of the base 1 and can slide towards the front positioning block 2, facilitating bidirectional positioning in conjunction with the front positioning block 2. Additionally, the end of the rear positioning block 3 that contacts the laser array 9 to be welded has an arc-shaped protrusion, which prevents the semiconductor laser chip 91 and the tungsten copper heat sink 92 from tilting due to excessive force. During positioning, this arc-shaped protrusion contacts one side of the tungsten copper heat sink 92 in the laser array 9 to be welded.

[0055] Side-block positioning blocks 4 are located on both sides of the base 1 and are used to position the laser array 9 to be welded from both sides.

[0056] In this embodiment, the side guard positioning block 4 is fixedly installed on the left and right sides of the base 1 for positioning on the left and right sides.

[0057] The array pressure block 5 is located at the upper end of the laser array to be welded, and is used to position the laser array to be welded from the upper end.

[0058] In this embodiment, after the laser array 9 to be welded is placed, the array pressure block 5 applies pressure from above to ensure that the tungsten copper heat sink 92 and the aluminum nitride ceramic 94 maintain good welding.

[0059] As can be seen, in this embodiment, the front positioning block 2, the rear positioning block 3, the side blocking positioning block 4, and the array pressing block 5 perform all-round positioning of the laser array 9 to be welded in the front-back, left-right, and up-down directions, respectively. The zirconia ceramic 95 plays a role in the discrete and spaced positioning of the aluminum nitride ceramic 94, so that the laser array 9 to be welded can be precisely integrated during the welding process.

[0060] The multi-chip laser array welding apparatus provided in this disclosure pre-arranges multiple semiconductor laser chips 91 and tungsten copper heat sinks 92 alternately to form an assembly. Then, a whole sheet of AuSn solder 93 is laid on top of this assembly. Further, aluminum nitride ceramics 94 and zirconium oxide ceramics 95 are alternately placed on the AuSn solder 93 to form a laser array 9 to be welded. Finally, the laser array 9 is precisely positioned, enabling the multiple semiconductor laser chips 91 to be integrated and welded together in a single high-temperature operation, as well as between the semiconductor laser chips 91 and the individual insulating ceramics (aluminum nitride ceramics 94), avoiding damage to the chips caused by multiple high-temperature welding processes. Simultaneously, hard solder is used on all welding surfaces, avoiding the chip degradation defects caused by fatigue due to prolonged high-temperature operation of soft solder, thus improving the chip's lifespan.

[0061] According to embodiments of this disclosure, the multi-chip laser array welding apparatus may further include: a chip front cavity positioning ceramic 6, a side positioning ceramic 7, and a rear slider 8.

[0062] The chip front cavity positioning ceramic 6 is fixedly mounted on the base 1. The rear positioning block 3 has a groove that matches the chip front cavity positioning ceramic 6, and the two form a slide rail structure, so that the rear positioning block 3 can slide along the chip front cavity positioning ceramic 6.

[0063] In this embodiment, the chip front cavity positioning ceramic 6 has no metal layer and is an insulating component. Its surface is mirror-polished to prevent the chip front cavity from being scratched.

[0064] The side positioning ceramic 7 is located between the side blocking positioning block 4 and the laser array 9 to be welded, and is used to maintain the neatness of the laser array 9 to be welded under the positioning action of the side blocking positioning block 4.

[0065] In this embodiment, the side positioning ceramic 7 is disposed on both sides of the laser array 9 to be welded, and the side blocking positioning block 4 can position the laser array 9 to be welded from both sides through the side positioning ceramic 7. The side positioning ceramic 7 has no metal layer on its surface and is an insulating component, and its height is located in the middle position of the aluminum nitride ceramic 13 in the unwelded laser array 9.

[0066] The rear slider 8 is mounted on the rear positioning block 3 and can slide together with the rear positioning block 3 to perform rear positioning. During positioning, the rear slider 8 contacts the aluminum nitride ceramic side of the laser array 9 to be welded.

[0067] According to the embodiments of this disclosure, the base 1, the front positioning block 2, the rear positioning block 3, the side blocking positioning block 4, the array pressure block 5, and the rear slider 8 are all made of tungsten copper material with a low coefficient of thermal expansion to prevent the welding accuracy and welding quality of the laser array from being affected during high-temperature welding.

[0068] The multi-chip laser array welding apparatus provided in this embodiment uses tungsten copper material with a low coefficient of thermal expansion. This not only avoids the problem of excessive stress caused by the large coefficient of thermal expansion of the material during the welding process, thereby improving the welding quality, but also achieves precise positioning of multiple laser chips, heat sinks, and discrete aluminum nitride ceramics, further realizing high-precision integrated welding of multi-chip laser arrays.

[0069] In this embodiment, aluminum nitride ceramics 94 and zirconia ceramics 95 are alternately arranged on the AuSn solder sheet 93. That is, the aluminum nitride ceramics 94 can be set separately first, and then the zirconia ceramics 95 can be set between the aluminum nitride ceramics 94 to fill the gaps and position the aluminum nitride ceramics 94, so that each aluminum nitride ceramic 94 is precisely positioned directly above each tungsten copper heat sink 92. The zirconia ceramics 95 have no metal layer on their surface and are insulating components.

[0070] The coefficient of thermal expansion of aluminum nitride ceramic 94 is 5.6 × 10⁻⁶. -6 At ℃, the coefficient of thermal expansion of zirconia ceramic 95 is 10.5 × 10⁻⁶. -6 / ℃, in comparison, the coefficient of thermal expansion of zirconia ceramic 95 is significantly greater than that of aluminum nitride ceramic 94. Therefore, after high-temperature welding and solidification, the gaps between aluminum nitride ceramic 94 become larger, and zirconia ceramic 95 can be easily removed.

[0071] The multi-chip laser array welding apparatus provided in this disclosure can effectively release the stress on the chip caused by all-hard solder welding through discrete aluminum nitride ceramic welding, thereby further improving the service life of semiconductor lasers.

[0072] Based on the chip laser array welding apparatus of the present disclosure, the present disclosure also provides a multi-chip laser array welding method, which may include operations S1 to S5.

[0073] In operation S1, acquire the laser array 9 to be welded.

[0074] In operation S2, the laser array 9 to be welded is placed at the preset position of the multi-chip laser array welding device.

[0075] In operation S3, the multi-chip laser array welding device is used to position the laser array 9 to be welded.

[0076] In operation S4, the laser array to be welded after positioning is welded. In this process, the gold-tin alloy solder sheet melts at high temperature and flows to the metal layer. It will automatically break off at the location without the metal layer, thus completing the welding between the semiconductor laser chip and the tungsten copper heat sink, and between the tungsten copper heat sink and the aluminum nitride ceramic.

[0077] In operation S5, after condensation, the zirconia ceramic is removed to obtain the welded multi-chip laser array.

[0078] To achieve optimal welding results, the laser array 9 to be welded can be obtained, for example, through the following methods.

[0079] In this embodiment, for example, the laser array 9 to be welded can be obtained using three semiconductor laser chips 91 and four tungsten copper heat sinks 92. Specifically:

[0080] Starting from the position of the front positioning block 2, first place the tungsten copper heat sink 92, then place the semiconductor laser chip 91, and place the two alternately in sequence.

[0081] In this configuration, the first tungsten-copper heat sink 92 is welded to the P-side of the semiconductor laser chip 91, acting as the positive electrode. The second and third tungsten-copper heat sinks 92 are welded to the N-side of the semiconductor laser chip 91 on one side and to the P-side on the other side, effectively connecting the positive and negative electrodes of the chip in series. The fourth tungsten-copper heat sink 92 is welded to the N-side of the semiconductor laser chip 91, forming the negative electrode of the array. The welding surfaces of the tungsten-copper heat sinks 92 can have a pre-formed solder layer or can use solder pads.

[0082] The length of the tungsten copper heat sink 92 is the same as the length of the semiconductor laser chip 91, and its height is slightly higher than that of the semiconductor laser chip 91. This is to prevent the solder from adhering to the rear cavity surface of the semiconductor laser chip 91 in a molten state during high-temperature welding, which would cause a short circuit between the P and N surfaces.

[0083] The front cavity of the semiconductor laser chip 91 and one side of the tungsten copper heat sink 92 are placed on the chip front cavity positioning ceramic 6. The chip front cavity positioning ceramic 6 is mirror polished, which can ensure the neatness of the laser array emitting surface and avoid scratching the front cavity of the semiconductor laser chip 91.

[0084] The semiconductor laser chip 91 and the tungsten copper heat sink 92 are positioned left and right by the side positioning ceramics 7 on both sides, and the rear positioning block 3 makes the multiple semiconductor laser chips 91 and the tungsten copper heat sink 92 in close contact and position.

[0085] An entire AuSn solder pad 93 is placed on the semiconductor laser chip 91 and the tungsten copper heat sink 92. The size of the AuSn solder pad 93 is consistent with the combined size of the semiconductor laser chip 91 and the tungsten copper heat sink 92. Compared with using individual solder pads to position each tungsten copper heat sink 92 and aluminum nitride ceramic 94, which cannot be accurately positioned due to the large number of dispersed components in the array, using an entire AuSn solder pad 93 is more suitable for multi-chip array welding.

[0086] Aluminum nitride ceramics 94 and zirconia ceramics 95 are alternately placed on the AuSn solder pad 93, i.e., arranged in a staggered order. The number and placement of the aluminum nitride ceramics 94 correspond one-to-one with the number and placement of the tungsten copper heat sink 92. The zirconia ceramic 95 has no pre-formed metal layer on its surface and is an insulating component. The soldering surface of the aluminum nitride ceramic 94 has a pre-formed metal layer, while the non-soldering surfaces remain insulated. The height of the zirconia ceramic 95 is slightly lower than that of the aluminum nitride ceramic 94. The discrete aluminum nitride ceramics 94 effectively release the stress caused to the chip by the all-hard solder bonding process.

[0087] Thus, the laser array 9 to be welded is composed of the semiconductor laser chip 91, the tungsten copper heat sink 92, the AuSn solder pad 93, and the corresponding aluminum nitride ceramic 94 and zirconium oxide ceramic 95. The specific structure of this laser array 9 is shown in [reference needed]. Figure 2 As shown.

[0088] Figure 2 A schematic diagram of a laser array to be welded according to an embodiment of the present disclosure is shown.

[0089] like Figure 2 As shown, the laser array 9 to be welded in this embodiment includes: a semiconductor laser chip 91, a tungsten copper heat sink 92, an AuSn solder pad 93, an aluminum nitride ceramic 94, and a zirconium oxide ceramic 95.

[0090] An array pressure block 5 is placed on top of the laser array 9 to be welded. Since the height of the zirconia ceramic 95 is slightly lower than that of the aluminum nitride ceramic 94, the pressure of the array pressure block 5 will be entirely applied to the aluminum nitride ceramic 94, ensuring the welding quality of the tungsten copper heat sink 92 and the aluminum nitride ceramic 94. A rear slider 8 is placed at the rear end of the laser array 9 to be welded to fix multiple aluminum nitride ceramics 94 and zirconia ceramics 95.

[0091] During high-temperature welding, a single AuSn solder pad 93, in a molten state under high temperature, flows towards the metal layer, automatically breaking off at the location without a metal layer, thus completing the welding of the aluminum nitride ceramic 94 to the tungsten copper heat sink 92. This ultimately achieves the welding between the semiconductor laser chip 91 and the tungsten copper heat sink 92, and between the tungsten copper heat sink 92 and the aluminum nitride ceramic 94.

[0092] The coefficient of thermal expansion of aluminum nitride ceramic 94 is 5.6 × 10⁻⁶. -6 At ℃, the coefficient of thermal expansion of zirconia ceramic 95 is 10.5 × 10⁻⁶. -6 / ℃, in comparison, the coefficient of thermal expansion of zirconia ceramic 95 is significantly greater than that of aluminum nitride ceramic 94. Therefore, after high-temperature welding and condensation, the gaps between aluminum nitride ceramics 94 become larger, and zirconia ceramic 95 can be easily removed, ultimately forming the welded laser array 10. The structure of the welded laser array 10 is shown in Figure 3.

[0093] Figure 3 A schematic diagram of a laser array welded according to an embodiment of the present disclosure is shown.

[0094] like Figure 3 As shown, the laser array 10 after welding in this embodiment includes: a semiconductor laser chip 91, a tungsten copper heat sink 92, and an aluminum nitride ceramic 94.

[0095] It should be understood that the multi-chip laser array welding method provided in this disclosure is applicable to welding of other hard solders as well as welding of other semiconductor laser chips.

[0096] The flowcharts and block diagrams in the accompanying drawings illustrate the architecture, functionality, and operation of possible implementations of systems, methods, and computer program products according to various embodiments of the present disclosure. In this regard, each block in a flowchart or block diagram may represent a module, segment, or portion of code containing one or more executable instructions for implementing a specified logical function. It should also be noted that in some alternative implementations, the functions indicated in the blocks may occur in a different order than those indicated in the drawings. For example, two consecutively indicated blocks may actually be executed substantially in parallel, and they may sometimes be executed in reverse order, depending on the functions involved. It should also be noted that each block in a block diagram or flowchart, and combinations of blocks in a block diagram or flowchart, may be implemented using a dedicated hardware-based system that performs the specified function or operation, or using a combination of dedicated hardware and computer instructions. Those skilled in the art will understand that the features described in the various embodiments of the present disclosure can be combined and / or combined in various ways, even if such combinations are not explicitly described in the present disclosure. In particular, the features described in the various embodiments of this disclosure may be combined and / or combined in various ways without departing from the spirit and teachings of this disclosure. All such combinations and / or combinations fall within the scope of this disclosure.

[0097] The embodiments of this disclosure have been described above. However, these embodiments are for illustrative purposes only and are not intended to limit the scope of this disclosure. Although various embodiments have been described above, this does not mean that the measures in the various embodiments cannot be used advantageously in combination. Various substitutions and modifications can be made by those skilled in the art without departing from the scope of this disclosure, and all such substitutions and modifications should fall within the scope of this disclosure.

Claims

1. A multi-chip laser array bonding method, wherein, The multi-chip laser array comprises semiconductor laser chips and tungsten-copper heat sinks arranged alternately, and the welding surfaces of the tungsten-copper heat sinks and the semiconductor laser chips are provided with gold-tin solder layers, and the method comprises the following steps: Obtaining a laser array to be welded; Placing the laser array to be welded at a preset position of a multi-chip laser array welding device, wherein the multi-chip laser array welding device comprises: a base for placing the laser array to be welded; a front end positioning block arranged at one end of the base for positioning the laser array to be welded from one end; a rear end positioning block movably arranged at the other end of the base for positioning the laser array to be welded from the other end in cooperation with the front end positioning block; side stop positioning blocks arranged at both sides of the base for positioning the laser array to be welded from both sides; an array pressing block arranged at the upper end of the laser array to be welded for positioning the laser array to be welded from the upper end; the upper ends of the semiconductor laser chips and the tungsten-copper heat sinks are paved with whole gold-tin alloy solder pieces, the size of the gold-tin alloy solder pieces is consistent with the combination of the semiconductor laser chips and the tungsten-copper heat sinks, the upper ends of the gold-tin alloy solder pieces are alternately provided with aluminum nitride ceramics and zirconium oxide ceramics, the number and placement position of the aluminum nitride ceramics correspond to the number and placement position of the tungsten-copper heat sinks one by one, and the welding surface of the aluminum nitride ceramics is configured as a metal layer and the non-welding surface is configured as an insulating layer; positioning the laser array to be welded by using the multi-chip laser array welding device; welding the laser array to be welded after positioning, wherein the gold-tin alloy solder pieces become molten at high temperature and flow to the metal layer, and are automatically disconnected at positions without metal layer, thereby completing the welding between the semiconductor laser chips and the tungsten-copper heat sinks, the tungsten-copper heat sinks and the aluminum nitride ceramics; removing the zirconium oxide ceramics after condensation to obtain the welded multi-chip laser array.

2. The method of claim 1, wherein, One side of the base for placing the laser array to be welded is arranged at a preset angle.

3. The method of claim 2, wherein, The device further comprises: a chip front cavity positioning ceramic arranged on the base; wherein the rear end positioning block is provided with a groove matched with the chip front cavity positioning ceramic, so that the rear end positioning block can slide along the chip front cavity positioning ceramic.

4. The method of claim 3, wherein, The chip front cavity positioning ceramic is configured as an insulator, and the surface thereof is pre-processed by mirror polishing.

5. The method of claim 3, wherein, The end of the rear end positioning block in contact with the laser array to be welded is provided with an arc-shaped protrusion. The arc-shaped protrusion is in contact with one side of the tungsten-copper heat sink during positioning.

6. The method of claim 2, wherein, The device further comprises: a side positioning ceramic arranged between the side stop positioning block and the laser array to be welded for maintaining the neatness of the laser array to be welded under the positioning action of the side stop positioning block; wherein the surface of the side positioning ceramic is configured as an insulator.

7. The method of claim 2, wherein, The device further comprises: a rear end sliding block arranged on the rear end positioning block and capable of sliding together with the rear end positioning block; wherein the rear end sliding block is in contact with one side of the aluminum nitride ceramic during positioning.

8. The method of claim 7, wherein, The base, the front end positioning block, the rear end positioning block, the side stop positioning block, the array pressing block and the rear end sliding block are made of tungsten copper material with low thermal expansion coefficient.

9. The method of claim 2, wherein, The aluminum nitride ceramic has a thermal expansion coefficient of 5.6 x 10 -6 / °C, and the zirconia ceramic has a thermal expansion coefficient of 10.5 x 10 -6 / °C.

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