CN219598333U - Laser welding device and wafer repairing equipment - Google Patents

Abstract

The utility model belongs to the technical field and discloses a laser welding device and wafer repairing equipment, wherein the laser welding device comprises a laser transmitter, the laser transmitter is configured to transmit a laser beam to a substrate, the cross section of the laser beam is annular, an inner ring of the cross section at the position of the laser beam which is level with the first surface of a workpiece surrounds the periphery of the first surface, and the first surface is the surface of one side of the workpiece away from the substrate. The laser transmitter transmits the annular laser beam to prevent the laser from directly acting on the DBR coating on the surface of the chip, so that the heating efficiency of the laser is effectively ensured, the welding supplement is prevented from being heated and melted by increasing the laser power, and the chip and the substrate are prevented from being damaged while the welding supplement can be heated and melted. The wafer repairing device comprising the laser welding device can prevent the chip and the substrate from being damaged while ensuring that the welding supplement can be heated and melted.

Description

Laser welding device and wafer repairing equipment

Technical Field

The utility model relates to the technical field of semiconductor packaging, in particular to a laser welding device and wafer repairing equipment.

Background

The LED display panel manufacturing process comprises an LED chip packaging step, wherein the LED chip packaging process comprises the steps of dipping an LED chip in solder paste through a die bonder, transferring the LED chip onto a PCB substrate in an array mode, welding the chip on a bonding pad in a reflow soldering mode, and then performing technological processes such as dispensing and the like. In this process, there are some bad points on the substrate caused by that some chips are not accurately soldered on the pads of the substrate, and the substrate with the bad points needs to be repaired. The repair process is to firstly de-solder the bad unit wafer to separate the chip from the bonding pad, then supplement solder paste or soldering flux and other soldering supplements on the bonding pad, and take a new chip for re-soldering.

At present, new chips are welded on a substrate in the process of repairing the substrate mostly through manual welding, specifically, a worker heats the substrate through a heat gun to melt a welding supplement, but the heating rate of the heat gun is far lower than the heat absorption and heat dissipation rate of the substrate, therefore, the substrate needs to be preheated before welding, that is, the substrate needs to be placed on a heating table first, and after the substrate is completely preheated, the heat gun welding is performed.

For this reason, in the prior art, a laser welding method is generally used instead of manual welding, specifically, a laser emitter emits a surface-type laser toward a chip placed on a substrate, the laser irradiates the surface of the chip, and heat is transferred to a welding supplement through the chip, thereby realizing heating and melting of the welding supplement.

However, in the prior art, there is a backlight LED chip, and the use of the chip as an LCD backlight source has a better light source effect, specifically, the surface of the chip is generally plated with a DBR (distributed bragg reflector) plating layer, and the DBR plating layer has two main functions: firstly, strengthen the light efficiency, secondly, block the highlight that the chip openly goes out, make the whole light efficiency in chip side and front more even to obtain better display effect. For the chip, if the surface laser is used for welding, most of the laser irradiated on the surface of the chip is reflected, so that the heating efficiency is low, meanwhile, the heat dissipation of the substrate is high, and the welding supplement can not be heated and melted, so that the laser power needs to be increased, but the chip and the substrate are damaged due to overlarge laser power, and the product is scrapped.

Therefore, the above-described problems are to be solved.

Disclosure of Invention

The utility model aims to provide a laser welding device and wafer repairing equipment, which are used for avoiding damaging a chip and a substrate while ensuring that a welding supplement can be heated and melted.

To achieve the purpose, the utility model adopts the following technical scheme:

in one aspect, the present utility model provides a laser welding apparatus for welding a workpiece to a substrate, the laser welding apparatus comprising:

and the laser emitter is configured to emit a laser beam to the substrate, the cross section of the laser beam is annular, an inner ring of the cross section of the laser beam at the position of being flush with the first surface of the workpiece surrounds the periphery of the first surface, and the first surface is the surface of one side of the workpiece away from the substrate.

Preferably, the laser welding apparatus further comprises a drive mechanism configured to drive the laser emitter to move towards or away from the substrate.

Preferably, the driving mechanism includes:

the sliding rail is fixedly arranged on the mounting seat;

the laser transmitter is connected to the sliding rail in a sliding way through the sliding block; a kind of electronic device with high-pressure air-conditioning system

The driving piece is fixedly installed on the installation seat and is configured to drive the sliding block to slide along the sliding rail.

Preferably, the laser welding apparatus further comprises a first sensor configured to detect a spacing between the laser transmitter and the substrate.

Preferably, the laser beam is a cylinder, and the cylinder is hollow.

Preferably, the laser beam is a table body, and the table body is hollow.

Preferably, the laser beam forms a light spot on the substrate as a rectangular ring, and an inner ring of the rectangular ring is positioned at an outer periphery of a bonding pad arranged on the substrate.

Preferably, the light spot formed by the laser beam on the substrate is an elliptical ring, and an inner ring of the elliptical ring is positioned at the periphery of a bonding pad arranged on the substrate.

Preferably, the laser welding apparatus further comprises a second sensor configured to detect a temperature of the substrate, the second sensor being electrically connected to the laser emitter.

In another aspect, the present utility model also provides a wafer repair apparatus, including a desoldering device configured to break a weld between a workpiece and a substrate, and a laser welding device as described above, the laser welding device being configured to re-weld the workpiece to the substrate.

The utility model has the beneficial effects that: in the utility model, the laser emitter can emit an annular light beam to the substrate, the laser beam does not irradiate on the DBR coating on the surface of the chip, but directly irradiates on the substrate, a light spot formed on the substrate surrounds the periphery of a bonding pad positioned on the substrate, and heat generated by laser irradiated on the substrate can be transferred from the periphery of the bonding pad to the bonding pad, so that the welding supplement is heated and melted. The laser emitter emits the annular laser beam to prevent the laser from directly acting on the DBR coating on the surface of the chip, so that the heating efficiency of the laser is effectively ensured, the welding supplement is prevented from being heated and melted by increasing the laser power, and the chip and the substrate are prevented from being damaged while the welding supplement can be heated and melted. The wafer repairing device comprising the laser welding device can prevent the chip and the substrate from being damaged while ensuring that the welding supplement can be heated and melted.

Drawings

FIG. 1 is a schematic view of a laser welding apparatus in an embodiment of the present utility model;

FIG. 2 is a schematic diagram of a laser beam in a first embodiment of the utility model;

FIG. 3 is a schematic diagram of a laser beam in a second embodiment of the utility model;

FIG. 4 is a schematic view of a spot in a first embodiment of the utility model;

fig. 5 is a schematic view of a spot in a third embodiment of the utility model.

In the figure:

100. a workpiece;

200. a substrate; 210. a bonding pad;

310. a laser emitter; 311. a laser beam; 3111. a light spot; 320. a driving mechanism; 321. a slide block; 322. a driving member; 330. and (5) a mounting seat.

Detailed Description

The utility model is described in further detail below with reference to the drawings and examples. It is to be understood that the specific embodiments described herein are merely illustrative of the utility model and are not limiting thereof. It should be further noted that, for convenience of description, only some, but not all of the structures related to the present utility model are shown in the drawings.

In the description of the present utility model, unless explicitly stated and limited otherwise, the terms "connected," "connected," and "fixed" are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally formed; can be mechanically or electrically connected; can be directly connected or indirectly connected through an intermediate medium, and can be communicated with the inside of two elements or the interaction relationship of the two elements. The specific meaning of the above terms in the present utility model will be understood in specific cases by those of ordinary skill in the art.

In the present utility model, unless expressly stated or limited otherwise, a first feature "above" or "below" a second feature may include both the first and second features being in direct contact, as well as the first and second features not being in direct contact but being in contact with each other through additional features therebetween. Moreover, a first feature being "above," "over" and "on" a second feature includes the first feature being directly above and obliquely above the second feature, or simply indicating that the first feature is higher in level than the second feature. The first feature being "under", "below" and "beneath" the second feature includes the first feature being directly under and obliquely below the second feature, or simply means that the first feature is less level than the second feature.

In the description of the present embodiment, the terms "upper", "lower", "left", "right", and the like are orientation or positional relationships based on those shown in the drawings, merely for convenience of description and simplicity of operation, and do not indicate or imply that the apparatus or elements referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as limiting the utility model. Furthermore, the terms "first," "second," and the like, are used merely for distinguishing between descriptions and not for distinguishing between them.

Example 1

Based on the foregoing description, and referring to fig. 2 and 3, the substrate 200 with the defective spot needs to be repaired, at present, a new chip is mostly welded on the substrate 200 by manual welding in the repairing process of the substrate 200, but manual welding is difficult to meet the industrial production requirement, and meanwhile, since reflow soldering consumes a long time, the method is suitable for welding a plurality of chips on the substrate 200 at one time, therefore, for welding a single chip, laser welding is generally adopted to replace manual welding in the prior art, but the laser welding device in the prior art is not suitable for welding a backlight LED chip.

In order to solve the above-mentioned problems, please refer to fig. 1, 2 and 4, the present embodiment provides a laser welding apparatus for welding a workpiece 100 onto a substrate 200, wherein the workpiece 100 is a backlight LED chip, the laser welding apparatus includes a laser emitter 310, the laser emitter 310 is configured to emit a laser beam 311 toward the substrate 200, the cross section of the laser beam 311 is annular, an inner ring of the cross section of the position where the laser beam 311 is flush with a first surface of the workpiece 100 surrounds the periphery of the first surface, and the first surface is a surface of the side of the workpiece 100 away from the substrate 200.

It should be noted that the workpiece 100 may be a backlight LED chip such as a Mini-LED chip or a Micro-LED chip, which is not particularly limited in this embodiment.

In the present embodiment, the laser emitter 310 can emit an annular beam toward the substrate 200, the laser beam 311 is not irradiated onto the DBR plating layer of the chip surface, but is directly irradiated onto the substrate 200, and the spot 3111 formed on the substrate 200 surrounds the outer periphery of the pad 210 positioned on the substrate 200, and heat generated by the laser irradiated onto the substrate 200 can be transferred from the outer periphery of the pad 210 to the pad 210, thereby heating and melting the soldering supplement. That is, the present embodiment prevents laser light from directly acting on the DBR plating layer on the surface of the chip by making the laser emitter 310 emit the laser beam 311 in a ring shape, so as to effectively ensure the heating efficiency of the laser light, thereby avoiding the need to increase the laser power to heat and melt the soldering supplement, so as to avoid damaging the chip and the substrate 200 while ensuring that the soldering supplement can be heated and melted.

Meanwhile, since the light spot 3111 formed on the substrate 200 surrounds the periphery of the bonding pad 210 located on the substrate 200, that is, the light spot 3111 formed on the substrate 200 is also annular, the annular light spot 3111 can effectively prevent the heat around the chip from being dissipated too quickly, that is, the embodiment can also effectively slow down the dissipation of the heat, so that the need of increasing the laser power to heat and melt the soldering supplement is further avoided, and the damage to the chip and the substrate 200 is further avoided while the soldering supplement can be heated and melted.

Specifically, when repairing the substrate 200, a worker first finds a defective spot by a microscope and picks up the defective spot under the microscope, so that the bonding between the chip at the defective spot and the substrate 200 is released, then a soldering supplement such as solder paste or flux is supplemented to the empty pad 210 from which the defective spot has been removed by a soldering device or worker, after the soldering supplement is supplemented to the empty pad 210, a new chip is supplemented to the pad 210 to which the soldering supplement has been supplemented by a die bonding device or worker, then an annular beam is emitted to the substrate 200 by a laser emitter 310, the periphery of the pad 210 in the defective area is irradiated, then laser is continuously irradiated and heated until the soldering supplement is melted and molded, then the laser emitter 310 is turned off, the soldering supplement is solidified, and the chip bonding is completed.

It can be appreciated that the outer periphery of the bonding pad 210 is generally coated with a white oil material, so that the laser welding device in the prior art needs to increase the laser power to finish welding, and the white oil material is easy to be damaged when the laser with increased power irradiates onto the white oil material, while the welding can be realized without increasing the laser power, so that the white oil material is not easy to be damaged when the laser irradiated onto the white oil material is realized.

In this embodiment, the preset temperature of the laser emitted by the laser emitter 310 does not exceed the tolerance temperature of the white oil material, which is generally below 400 ℃, and the heating process time of laser welding does not exceed 30 seconds, so as to further avoid damaging the chip and the substrate 200.

Based on the above, the present embodiment provides a wafer repair apparatus for repairing a substrate 200 when a defective spot exists on the substrate 200, the wafer repair apparatus including a desoldering device (not shown in the drawing) configured to release the soldering between a workpiece 100 and the substrate 200 and a laser soldering device configured to re-solder the workpiece 100 to the substrate 200, the wafer repair apparatus including the above-described laser soldering device being capable of avoiding damage to the chip and the substrate 200 while ensuring that a soldering supplement can be melted by heating.

It can be understood that the welding disassembly device comprises a microscope, the worker can find and pick out the bad point location through the microscope, the structure of the microscope is the prior art, and the description of the structure is omitted in the embodiment.

Based on the foregoing, the wafer repair apparatus in this embodiment further includes a tin replenishment device for replenishing the solder paste or the soldering flux and the like on the vacancy pad 210, and a die bonding device for replenishing the new chip on the pad 210 replenished with the solder paste or the like, however, in other alternative embodiments, the wafer repair apparatus may be configured to not include the tin replenishment device and the die bonding device, but to replenish the solder paste or the new chip manually, which is not particularly limited in this embodiment.

The above-mentioned wafer repair equipment has the following working steps:

s1, a worker finds out a bad point through a microscope of a desoldering device, and picks up the bad point under the microscope, so that the welding between a chip at the bad point and the substrate 200 is relieved;

s2, supplementing soldering supplements such as solder paste or soldering flux on the empty bonding pads 210 from which bad points have been removed by a tin supplementing device or a worker;

s3, supplementing a new chip on the welding pad 210 which is supplemented with the welding supplement by a die bonding device or a worker;

s4, the laser emitter 310 emits a laser beam 311 to the substrate 200;

s5, continuously radiating and heating by laser until the welding supplement is melted and formed;

s6, turning off the laser emitter 310, and solidifying the welding supplement.

Preferably, the laser welding apparatus in this embodiment further includes a driving mechanism 320, where the driving mechanism 320 is configured to drive the laser emitter 310 to move toward or away from the substrate 200, so as to adjust the distance between the laser emitter 310 and the substrate 200, thereby further ensuring that the heat generated by the laser irradiated onto the substrate 200 can heat and melt the welding supplement, so as to avoid a large energy loss generated in the process of irradiating the laser onto the substrate 200 due to the overlarge distance between the laser emitter 310 and the substrate 200.

In this embodiment, the driving mechanism 320 preferably includes a sliding rail (not shown in the drawings), a sliding block 321 and a driving member 322, the sliding rail is fixedly mounted on the mounting seat 330, the laser transmitter 310 is slidably connected to the sliding rail through the sliding block 321, the driving member 322 is fixedly mounted on the mounting seat 330, and the driving member 322 is configured to drive the sliding block 321 to slide along the sliding rail, so that the laser transmitter 310 can move towards or away from the substrate 200, and in this embodiment, the driving mechanism 320 is simple in structure and low in cost.

It is to be understood that the driving member 322 may be a cylinder, an electric cylinder, or a linear driving structure such as an electric push rod, which is not particularly limited in this embodiment.

Further, the laser welding apparatus in this embodiment further includes a first sensor (not shown in the drawings) configured to detect the distance between the laser transmitter 310 and the substrate 200, so as to precisely control the distance between the laser transmitter 310 and the substrate 200, to further ensure that the heat generated by the laser irradiated onto the substrate 200 can heat and melt the welding supplement.

It can be understood that the structure and the working principle of the first sensor are both in the prior art, and this will not be described in detail in this embodiment.

Preferably, the laser beam 311 emitted by the laser emitter 310 in this embodiment is a column, the column is hollow, and the chip and the bonding pad 210 are both located inside the laser beam 311, so as to ensure that the laser beam 311 does not irradiate on the DBR plating layer on the chip surface.

In the present embodiment, the spot 3111 formed on the substrate 200 by the laser beam 311 is preferably a rectangular ring, the inner ring of which is located at the outer periphery of the pad 210 provided on the substrate 200, and the heat generated by the laser irradiated on the substrate 200 can be transferred from the outer periphery of the pad 210 to the pad 210, thereby heating and melting the soldering supplement.

Further, the laser welding apparatus in this embodiment further includes a second sensor, the second sensor is configured to detect the temperature of the substrate 200, the second sensor is electrically connected to the laser emitter 310, when the temperature of the substrate 200 is too high, the second sensor can transmit a signal to the laser emitter 310, and the laser emitter 310 receiving the signal can be turned off, so as to further avoid damaging the chip and the substrate 200.

It can be understood that the structure and the working principle of the second sensor are both in the prior art, and this will not be described in detail in this embodiment.

Example two

Referring to fig. 3, compared with the first embodiment, the difference of the present embodiment is that the laser beam 311 emitted by the laser emitter 310 is a platform body, the platform body is hollow, and the chip and the bonding pad 210 are both located inside the laser beam 311, so as to ensure that the laser beam 311 does not irradiate on the DBR plating layer on the chip surface.

In this embodiment, the driving member 322 can control the laser transmitter 310 to move toward or away from the substrate 200, so that the inner ring of the cross section at the position where the laser beam 311 is flush with the first surface of the workpiece 100 can be precisely controlled to surround the periphery of the first surface, so as to effectively ensure that the laser beam 311 does not irradiate on the DBR plating layer on the chip surface.

Example III

Referring to fig. 5, compared with the first embodiment, the difference between the present embodiment is that the spot 3111 formed on the substrate 200 by the laser beam 311 is an elliptical ring, the inner ring of the elliptical ring is located at the outer periphery of the bonding pad 210 disposed on the substrate 200, and the heat generated by the laser irradiated on the substrate 200 can be transferred from the outer periphery of the bonding pad 210 to the bonding pad 210, so as to heat and melt the soldering supplement.

Of course, in other alternative embodiments, the inner ring and the outer ring of the light spot 3111 formed on the substrate 200 may be circular or polygonal, which is only required to ensure that the light spot 3111 is annular and the inner ring of the light spot 3111 is located at the periphery of the bonding pad 210, which is not limited in this embodiment.

It is to be understood that the above examples of the present utility model are provided for clarity of illustration only and are not limiting of the embodiments of the present utility model. Various obvious changes, rearrangements and substitutions can be made by those skilled in the art without departing from the scope of the utility model. It is not necessary here nor is it exhaustive of all embodiments. Any modification, equivalent replacement, improvement, etc. which come within the spirit and principles of the utility model are desired to be protected by the following claims.

Claims (10)

1. A laser welding apparatus for welding a workpiece (100) to a substrate (200), the laser welding apparatus comprising:

a laser emitter (310) configured to emit a laser beam (311) toward the substrate (200), the laser beam (311) having a circular cross section, an inner ring of the cross section at a position where the laser beam (311) is flush with a first surface of the workpiece (100), the first surface being a surface of a side of the workpiece (100) remote from the substrate (200), surrounding an outer circumference of the first surface.

2. The laser welding device of claim 1, further comprising a drive mechanism (320), the drive mechanism (320) configured to drive the laser transmitter (310) toward or away from the substrate (200).

3. The laser welding apparatus according to claim 2, wherein the driving mechanism (320) includes:

the sliding rail is fixedly arranged on the mounting seat (330);

the laser transmitter (310) is connected to the sliding rail in a sliding way through the sliding block (321); a kind of electronic device with high-pressure air-conditioning system

And the driving piece (322) is fixedly arranged on the mounting seat (330), and the driving piece (322) is configured to drive the sliding block (321) to slide along the sliding rail.

4. The laser welding device of claim 2, further comprising a first sensor configured to detect a spacing between the laser transmitter (310) and the substrate (200).

5. The laser welding apparatus according to claim 1, wherein the laser beam (311) is a cylinder, the cylinder being hollow.

6. The laser welding apparatus according to claim 1, wherein the laser beam (311) is a table body, and the table body is hollow.

7. The laser welding apparatus according to claim 5 or 6, wherein a spot (3111) of the laser beam (311) formed on the substrate (200) is a rectangular ring, an inner ring of which is located at an outer periphery of a pad (210) provided on the substrate (200).

8. The laser welding apparatus according to claim 5 or 6, wherein a spot (3111) of the laser beam (311) formed on the substrate (200) is an elliptical ring, an inner ring of which is located at an outer periphery of a pad (210) provided on the substrate (200).

9. The laser welding device of claim 1, further comprising a second sensor configured to detect a temperature of the substrate (200), the second sensor being electrically connected to the laser transmitter (310).

10. Wafer repair apparatus comprising a de-soldering device configured to release a weld between a workpiece (100) and a substrate (200) and a laser welding device according to any of claims 1-9 configured to re-weld the workpiece (100) to the substrate (200).