A stress relieved bar package array and laser

Abstract

This invention relates to a stress-relief bar packaging array and a laser. The stress-relief bar packaging array includes multiple laser bar modules, an insulating base, and multiple conductive elements. The conductive elements are spaced apart on the surface of the insulating base. The laser bar modules are independent of each other and electrically connected to adjacent conductive elements to form a series connection between the multiple laser bar modules. This invention, based on the principle of electrically connecting conductive elements to the laser bar modules (i.e., not connecting the laser bar modules themselves), can reduce quality defects caused by packaging stress during the packaging process, achieving a product packaging pass rate of over 99%. It also enables stable operation with a pulse width of hundreds of milliseconds and a duty cycle of over 40%. The structure is simple, packaging is convenient, and it is suitable for mass production.

Description

Technical Field

[0001] This invention relates to the field of laser technology, and more particularly to a stress-relieving bar strip encapsulation array and a laser. Background Technology

[0002] Semiconductor lasers are widely used due to their advantages of high power, high brightness, and small size. In recent years, with the development of the industry, application fields have placed higher demands on semiconductor lasers. High duty cycles, pulse widths in the hundreds of milliseconds, and gold-tin packaging have gradually replaced continuous indium packaging technology. The technology of semiconductor lasers is becoming more and more mature and stable. At the same time, the replacement of indium packaging with gold-tin packaging has also presented new technical challenges to the industry. Gold-tin alloy is a hard solder. Compared with indium metal, which is known as a soft solder, its introduction has brought high reliability to lasers, but it has also brought greater stress and thermal stress problems to laser packaging. Especially in some semiconductor laser arrays with pulse widths in the hundreds of milliseconds and duty cycles exceeding 40%, chip cracking and burnout due to packaging stress and thermal stress frequently occur during the packaging process and testing, causing great trouble to the lifespan reliability and packaging pass rate of semiconductor laser arrays. The above problems urgently need to be solved. Summary of the Invention

[0003] This invention discloses a stress-relieving bar strip encapsulation array and a laser, aiming to solve the technical problems existing in the prior art.

[0004] The present invention adopts the following technical solution:

[0005] In a first aspect, the present invention provides a stress-relieving bar packaging array, which includes a plurality of laser bar modules, an insulating base, and a plurality of conductive elements; the plurality of conductive elements are spaced apart on the surface of the insulating base; the laser bar modules are independent of each other and are electrically connected to adjacent conductive elements to form a series electrical connection between the plurality of laser bar modules.

[0006] In the stress-relieving bar strip encapsulation of the present invention, the laser bar strip module includes a first heat sink, a bar strip, and a second heat sink; the first heat sink is welded to one side of the bar strip through a first solder layer and to one of the adjacent conductive elements through a second solder layer; the second heat sink is welded to the other side of the bar strip through the first solder layer and to the other of the adjacent conductive elements through the second solder layer.

[0007] In the stress-relieving bar packaging of the present invention, the first solder layer is a gold-tin solder layer with a thickness of 4 micrometers to 8 micrometers.

[0008] In the stress-relieving bar packaging of the present invention, the first solder layer is a gold-tin solder layer, wherein the mass ratio of gold to tin in the gold-tin solder layer is 80±5%:20±5%.

[0009] In the stress-relieving bar packaging of the present invention, the second solder layer is a tin-silver-copper solder layer with a thickness of 12-50 micrometers.

[0010] In the stress-relieving bar packaging of the present invention, the relative edges of adjacent conductive elements are parallel to form an insulating region; the insulating base has an insulating through groove corresponding to the position of the insulating region; the bar of the laser bar module is located directly above the insulating through groove.

[0011] In the stress-relieving bar strip encapsulation of the present invention, the interval between adjacent laser bar strip modules is greater than or equal to 0.

[0012] In the stress-relieving bar packaging of the present invention, a stress-buffering structure is filled between adjacent conductive elements.

[0013] In the stress-relieving bar packaging of the present invention, the conductive element is a metal conductive layer.

[0014] In the stress-relieving bar packaging of the present invention, the insulating base is a plate-shaped structure made of ceramic material, and the conductive elements are respectively disposed on both sides.

[0015] In a second aspect, the present invention also provides a laser comprising any of the stress-relief bar strip encapsulation arrays described above and a laser heat sink; the insulating base is welded to the laser heat sink via a third solder layer.

[0016] In the laser of the present invention, the third solder layer is an indium or indium tin solder layer.

[0017] The laser of the present invention includes a plurality of stress-relief bar packaging arrays; the stress-relief bar packaging arrays are connected in series.

[0018] The technical solution adopted in this invention can achieve the following beneficial effects:

[0019] This invention provides a stress-relief bar packaging array. Based on the electrical connection between conductive elements and laser bar modules, i.e., the laser bar modules are not connected to each other, the quality defects caused by packaging stress can be reduced during the packaging process, so that the product packaging qualification rate can reach more than 99%, and it can be used stably with a pulse width of hundreds of milliseconds and a duty cycle of more than 40%. The structure is simple, the packaging is convenient, and it is suitable for mass production. Attached Figure Description

[0020] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below, forming part of the present invention. The illustrative embodiments of the present invention and their descriptions explain the present invention and do not constitute an improper limitation of the present invention. In the accompanying drawings:

[0021] Figure 1 This is a schematic diagram of the structure of a stress-relieving bar strip encapsulation array according to the present invention;

[0022] Figure 2 This is a three-dimensional structural diagram of the laser of the present invention;

[0023] Figure 3 This is a schematic diagram of the internal structure of the laser heat sink of the present invention;

[0024] Figure 4 This is a schematic diagram of the internal structure of the laser heat sink of the present invention;

[0025] Figure 5 This is a schematic diagram of the main structure of the laser of the present invention;

[0026] Figure 6 This is a cross-sectional structural diagram of the laser of the present invention.

[0027] Explanation of reference numerals in the attached figures:

[0028] 1. Laser bar module; 11. First heat sink; 12. Bar; 13. Second heat sink; 2. Insulating base; 21. Insulating through groove; 3. Conductive element; 4. Insulating area; 5. Laser heat sink; 51. Heat sink body; 511. Cooling channel; 512. Inlet; 513. Outlet; 514. Flow guide; 52. First electrode; 53. Second electrode; 54. First insulating PCB board; 55. Second insulating PCB board. Detailed Implementation

[0029] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below in conjunction with specific embodiments and corresponding drawings. In the description of this invention, it should be noted that the term "or" is generally used to include the meaning of "and / or," unless otherwise expressly indicated.

[0030] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or a magnetic connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances. Furthermore, in the description of this application, the terms "first," "second," etc., are used only for distinguishing descriptions and should not be construed as indicating or implying relative importance. In the description of this invention, "a plurality of" means at least two, such as two, three, or more, unless otherwise explicitly specified.

[0031] Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0032] To address the problems existing in the prior art, this application provides a stress-relieving bar strip encapsulation array and a laser.

[0033] Example 1

[0034] This embodiment provides a stress-relieving bar strip encapsulation array, such as Figure 1 As shown, the stress-relieving bar strip encapsulation array A includes multiple laser bar strip modules 1, an insulating base 2, and multiple conductive elements 3; the multiple conductive elements 3 are spaced apart on the surface of the insulating base 2; the laser bar strip modules 1 are independent of each other and are electrically connected to two adjacent conductive elements 3 respectively, so as to form a series electrical connection between the multiple laser bar strip modules 1.

[0035] The present invention discloses a stress-relief bar strip packaging array, which is based on the electrical connection between the conductive element 3 and the laser bar strip module 1, i.e., the laser bar strip modules are not connected to each other. In this way, the quality defects caused by packaging stress can be reduced during the packaging process, so that the product packaging qualification rate can reach more than 99%, and it can be used stably with a pulse width of hundreds of milliseconds and a duty cycle of more than 40% (test conditions are 25°C and water flow rate of 2L / M). The structure is simple, the packaging is convenient, and it is suitable for mass production.

[0036] In some preferred embodiments, multiple laser bar modules 1 are arranged in parallel.

[0037] In some preferred embodiments, the laser bar module 1 includes a first heat sink 11, a bar 12, and a second heat sink 13. The first heat sink 11 is welded to one side of the bar 12 through a first solder layer and to one of the adjacent conductive elements 3 through a second solder layer. The second heat sink 13 is welded to the other side of the bar 12 through the first solder layer and to the other of the adjacent conductive elements 3 through the second solder layer. The method of clamping the bar 12 with the first heat sink 11 and the second heat sink 13 is beneficial for cooling the bar 12. The materials of the first heat sink 11 and the second heat sink 13 can be the same or different. The first heat sink 11, the bar 12, and the second heat sink 13 are welded together through the first solder layer to form a primary package, which can be reflow soldered in a reflow oven or a pick-and-place machine. After the primary package is formed, it is welded to the conductive element 3 through the second solder layer to form a secondary package, which can be reflow soldered in a reflow oven.

[0038] Preferably, the first heat sink 11 and the second heat sink 13 can be made of tungsten copper, such as W90Cu10, diamond copper, or metallized aluminum nitride ceramic; more preferably, the material is diamond copper, as this material has the best heat dissipation effect.

[0039] Preferably, the surfaces of the first heat sink 11 and the second heat sink 13 are plated with nickel gold or titanium platinum; thereby increasing solderability, increasing conductivity, and preventing solder from diffusing into the interior of the heat sink during soldering.

[0040] Preferably, the melting point of the first welding material layer is greater than that of the second welding material layer, so as to avoid the first welding material layer melting during the welding process.

[0041] In some preferred embodiments, the first solder layer is a gold-tin solder layer with a thickness of 4 to 8 micrometers; this ensures the normal operation of the laser. If the thickness is below the lower limit, there will be voids in the solder, which will cause the laser to fail during use. If the thickness is above the upper limit, the solder will overflow and block the functional area, i.e. the laser emission area, causing product failure.

[0042] In some preferred embodiments, the first solder layer is a gold-tin solder layer, in which the mass ratio of gold to tin is 80±5%:20±5%. Within this range, the performance of the laser can be guaranteed. If the ratio is outside the range, the packaging temperature will increase, resulting in increased product stress and reduced product life.

[0043] In some preferred embodiments, the second solder layer is a tin-silver-copper solder layer with a thickness of 12-50 micrometers. Within this range, the stress relief effect is good; outside this range, poor welding and poor stress relief will occur. If the thickness is too thin, poor welding or voids will occur. The presence of voids will cause a mismatch in the coefficient of thermal expansion, generating stress. If the thickness is too thick, solder will flow, which will easily affect the insulation area. More preferably, the weight ratio of each component of the tin-silver-copper solder layer is: tin (Sn): silver (Ag): copper (Cu) = 96.5:3:0.5. Based on this, the welding temperature is more accurate during welding, the control of the solder area is easier, and thus the stress relief effect is guaranteed.

[0044] In some preferred embodiments, the relative edges of adjacent conductive elements 3 are parallel to form an insulating region 4; an insulating groove 21 is provided on the insulating base 2 at the position corresponding to the insulating region 4; the bar 12 of the laser bar module 1 is located directly above the insulating groove 21 and is arranged parallel to the insulating groove 21; the insulating groove 21 can improve the insulation performance and the stress relief effect.

[0045] In some preferred embodiments, the interval between adjacent laser bar modules 1 is greater than or equal to 0; preferably, the interval is greater than 0; specifically, the interval size is determined according to the design requirements of the working condition. If the product size is sufficient and the required power is small, the interval can be increased to facilitate packaging; if the product size is insufficient and the required power is large, the interval is reduced to increase the width of the first heat sink 11 and the second heat sink 13 and improve heat dissipation performance.

[0046] In some preferred embodiments, a stress buffer structure is filled between adjacent conductive elements 3. The stress buffer structure is made of high-temperature resistant materials such as thermally conductive and / or conductive materials, and should ensure that no pollution is generated during operation; the use of thermally conductive and / or conductive materials increases the conductive or thermally conductive area of ​​the laser, thereby improving the heat dissipation effect.

[0047] Preferably, the stress buffer structure is made of a soft material such as indium-based solder, indium metal, indium-tin alloy metal, thermal grease, or silicone. More preferably, the stress buffer structure is made of indium metal to improve thermal conductivity without affecting the stress relief effect.

[0048] In some preferred embodiments, the conductive element 3 is a metal conductive layer.

[0049] Preferably, the conductive metal layer is a copper layer plated with nickel and gold; the thickness of the copper layer is determined by the magnitude of the laser's operating current; specifically, it can be determined by referring to data such as the current corresponding to the cross-sectional area of ​​the conductive material.

[0050] Preferably, multiple conductive elements 3 can be formed by slotting an insulating base 2 plated with a metal layer.

[0051] In some preferred embodiments, the insulating base 2 is a plate-shaped structure made of ceramic material, and conductive elements 3 are respectively provided on both sides; preferably, the insulating base 2 is made of aluminum nitride ceramic to improve thermal conductivity.

[0052] Example 2

[0053] This embodiment provides a laser, such as Figures 2-5 As shown, it includes the stress-relief bar strip encapsulation array A and the laser heat sink 5 in the above embodiment 1; the insulating base 2 is welded to the laser heat sink 5 through the third solder layer; the laser can be used as a side pump source surrounding the crystal bar, or it can be combined into a surface array for end-face pumping.

[0054] In some preferred embodiments, the third solder layer is an indium or indium-tin solder layer; its melting point is the same as that of the second solder layer.

[0055] In some preferred embodiments, multiple stress-relief bar package arrays are included; the stress-relief bar package arrays are connected in series; for example, the current series connection between multiple stress-relief bar package arrays is achieved by bridging electrodes, gold wire bonding, etc.

[0056] In some preferred embodiments, the laser heat sink 5 includes a heat sink body 51, a first electrode 52, a second electrode 53, a first insulating PCB board 54, and a second insulating PCB board 55. The heat sink body 51 has a cooling channel 511 extending along the arrangement direction of the bar strips 12 of the stress-relieving bar strip encapsulation array, with an inlet 512 formed on one side of the heat sink body 51 and an outlet 513 formed on the opposite side. The stress-relieving bar strip encapsulation array is disposed on the top surface of the heat sink body 51. The first insulating PCB board 54 and the second insulating PCB board 55 are fixed to the side of the heat sink body 51 adjacent to the top surface. The first electrode 52 is welded to the first insulating PCB board 54 through a fourth solder layer, and the second electrode 53 is welded to the second insulating PCB board 55 through a fourth solder layer. More preferably, a plurality of flow guides 514 are disposed within the cooling channel 511. The plurality of flow guides 514 are staggered to create turbulence in the flowing cooling medium, thereby improving the heat exchange effect.

[0057] The embodiments of the present invention have been described above with reference to the accompanying drawings. However, the present invention is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of the present invention without departing from the spirit and scope of the claims, and all of these forms are within the protection scope of the present invention.

Claims

1. A stress-relieving bar strip encapsulation array, characterized in that, Includes multiple laser bar modules, an insulating base, and multiple conductive components; Multiple conductive elements are spaced apart on the surface of the insulating base; The laser bar modules are independent of each other, the interval between adjacent laser bar modules is greater than or equal to 0, and each of the two adjacent conductive elements is electrically connected to form a series electrical connection between multiple laser bar modules; each laser bar module includes a first heat sink, a bar, and a second heat sink. The first heat sink is welded to one side of the bar strip through a first solder layer, and to one of the adjacent conductive elements through a second solder layer; The second heat sink is welded to the other side of the bar through the first solder layer, and to the other adjacent conductive element through the second solder layer.

2. The stress-relieving bar strip encapsulation array according to claim 1, characterized in that, The first solder layer is a gold-tin solder layer with a thickness of 4 to 8 micrometers.

3. The stress-relieving bar strip encapsulation array according to claim 1, characterized in that, The first solder layer is a gold-tin solder layer, and the mass ratio of gold to tin in the gold-tin solder layer is (80±5%):(20±5%).

4. The stress-relieving bar strip encapsulation array according to claim 1, characterized in that, The second solder layer is a tin-silver-copper solder layer with a thickness of 12-50 micrometers.

5. The stress-relieving bar strip encapsulation array according to any one of claims 1-4, characterized in that, The opposite edges of adjacent conductive elements are parallel, forming an insulating region; The insulating base has an insulating through groove corresponding to the position of the insulating area; The bar of the laser bar module is located directly above the insulating through slot.

6. The stress-relieving bar strip encapsulation array according to any one of claims 1-4, characterized in that, A stress-buffered structure is filled between adjacent conductive elements.

7. The stress-relieving bar strip encapsulation array according to any one of claims 1-4, characterized in that, The conductive element is a metal conductive layer.

8. The stress-relieving bar strip encapsulation array according to any one of claims 1-4, characterized in that, The insulating base is a plate-shaped structure made of ceramic material, and the conductive elements are respectively arranged on both sides.

9. A laser, characterized in that, Includes the stress-relief bar strip encapsulation array and laser heat sink as described in any one of claims 1-8; The insulating base is welded to the laser heat sink via a third layer of welding material.

10. The laser according to claim 9, characterized in that, The third solder layer is an indium or indium tin solder layer.

11. The laser according to claim 9, characterized in that, Includes multiple stress-relief bar encapsulation arrays; The stress-relieving bar strip encapsulation arrays are connected in series with each other.

Images