KR20130037331A

KR20130037331A - Laser processing device

Info

Publication number: KR20130037331A
Application number: KR1020110101686A
Authority: KR
Inventors: 홍준희; 송준오; 정주용
Original assignee: 엘지이노텍 주식회사
Priority date: 2011-10-06
Filing date: 2011-10-06
Publication date: 2013-04-16

Abstract

PURPOSE: A laser processing device is provided to improve the quality of individual chips by preventing damage to wafers due to heat generated when the wafers are cut by laser. CONSTITUTION: A laser processing device(100) comprises a laser generating part(110), multiple laser output parts(121,122), and a support member(20). The laser output parts are in parallel to a cut direction and radiates laser to workpieces so that the workpieces can be cut. The support member supports the workpieces and moves the laser output parts to the cut direction.

Description

Laser Processing Equipment {LASER PROCESSING DEVICE}

An embodiment relates to a laser processing apparatus.

In the semiconductor industry, a process of cutting a wafer into individual semiconductor chips is required. The wafer is cut into individual semiconductor chips and then processed into memory semiconductors, LEDs, and the like.

Conventionally, a laser was used when cutting a wafer. By using a laser in the wafer cutting apparatus using a laser according to the prior art, it is possible to reduce defects such as chipping (chipping) than when cutting the wafer by using a blade (blade) that rotates at a high speed. The chipping is a defect in which the edge of the semiconductor chip is broken, and the thinner the thickness of the wafer, the greater the impact on the reliability of the semiconductor chip.

However, in the case of cutting the wafer using a laser, an eluate due to the heat of the laser remains, deformation due to the heat is generated, and chipping defects are still generated.

Patent Document 10-2011-0089053 discloses a laser processing apparatus that performs effective processing by irradiating a plurality of lasers. However, there is a problem that a laser beam splitting member is required, and the output power of the laser is difficult.

The embodiment provides a laser processing apparatus which prevents wafers from being damaged by heat generated during wafer cutting by a laser, thereby improving the quality of individual chips.

The laser processing apparatus according to the embodiment includes a laser generating unit for generating a laser, a plurality of laser output units for cutting a workpiece by irradiating a workpiece with a laser generated by the laser generator, and supporting the laser beam. It includes a support member for moving the workpiece relative to the output unit, wherein the plurality of laser output unit may be disposed parallel to the cutting direction, spaced apart from each other.

Since the laser processing apparatus according to the embodiment cuts the wafer at several times by irradiating the laser scribe line superimposed on the wafer, it is possible to prevent thermal damage caused by the laser rather than cutting the wafer at once.

In addition, if the damage caused by the heat of the wafer is reduced, yield and quality are improved when the wafer is processed into a memory or an LED.

1A and 1B are schematic views illustrating a laser processing apparatus according to an embodiment.
2 is a view showing the operating principle of the laser processing apparatus of FIG.
3 is a view illustrating a principle of cutting a wafer by the laser processing apparatus according to the embodiment.
4 is a view showing a wafer cut by the laser processing apparatus according to the embodiment.
5A is a view illustrating a state in which a wafer is cut using a laser processing apparatus according to the related art.
5B is a view illustrating a state in which a wafer is cut using the laser processing apparatus according to the embodiment.
6 is a schematic view showing a laser processing apparatus according to another embodiment.
7 is a schematic view showing a laser processing apparatus according to another embodiment.

Advantages and features of the present invention and methods for achieving them will be apparent with reference to the embodiments described below in detail with the accompanying drawings. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. To fully disclose the scope of the invention to those skilled in the art, and the invention is only defined by the scope of the claims. Like reference numerals refer to like elements throughout.

The spatially relative terms " below ", " beneath ", " lower ", " above ", " upper " It can be used to easily describe the components and their correlations. Spatially relative terms are to be understood as including terms in different directions of the component in use or operation in addition to the directions shown in the figures. For example, when flipping a component shown in the figure, a component described as "below" or "beneath" of another component may be placed "above" of another device. have. Thus, the exemplary term "below" can include both downward and upward directions. The components can also be oriented in different directions, so that spatially relative terms can be interpreted according to orientation.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. In the present specification, the singular form includes plural forms unless otherwise specified in the specification. As used herein, “comprises” and / or “comprising” refers to a component, step, and / or operation that excludes the presence or addition of one or more other components, steps, and / or operations. I never do that.

Unless otherwise defined, all terms (including technical and scientific terms) used in the present specification may be used in a sense that can be commonly understood by those skilled in the art. Also, commonly used predefined terms are not ideally or excessively interpreted unless explicitly defined otherwise.

In the drawings, the thickness and size of components are exaggerated, omitted, or schematically illustrated for convenience and clarity of description. Also, the size and area of each component do not entirely reflect actual size or area.

In addition, the angle and direction mentioned in the process of demonstrating the structure to an Example are based on what was described in drawing. In the description of the structure of the component in the specification, if the reference point and the positional relationship with respect to the angle is not clearly mentioned, refer to the related drawings.

1A and 1B are schematic diagrams illustrating a laser processing apparatus according to an embodiment, FIG. 2 is a view illustrating an operating principle of the laser processing apparatus of FIG. 1, and FIG. 3 is a view illustrating a wafer processing apparatus according to an embodiment. 4 is a view showing a principle of cutting, Figure 4 is a view showing a wafer cut by a laser processing apparatus according to an embodiment, Figure 5a shows a state of cutting a wafer using a laser processing apparatus according to the prior invention. 5B is a view illustrating a state in which a wafer is cut using the laser processing apparatus according to the embodiment.

1A and 1B, the laser processing apparatus 100 includes a laser generating unit 110 for generating a laser and a plurality of laser output units 121 and 122 for irradiating the workpiece with the generated laser to cut the workpiece. And a support member 20 for holding the workpiece and relatively moving the plurality of laser output parts 121 and 122 in the cutting direction.

The plurality of laser output units 121 and 122 may be disposed in parallel to the cutting direction and spaced apart from each other.

The workpiece is not limited, but may include the wafer 10. Hereinafter, the description will be based on the wafer. The wafer 10 may be a semi-finished product for manufacturing a memory, an LED, and the like.

The laser generator 110 may generate a laser and may include any device capable of generating a laser. One or more laser generators 110 may be formed, and for example, may include a first laser generator 111 and a second laser generator 112. However, the present invention is not limited thereto and may have various numbers of laser generating units according to a working environment.

Here, the laser (LASER; Light Amplification by Stimulated Emission Radiation) means the light amplified by the induced emission process as interpreted in the solution, and unlike the light rays such as the sun rays (collimation), monochromatic ( Monochromatic, directional, coherent and other characteristics.

The laser generator 110 may be configured of, for example, a resonator, an optical amplifier, and a pump. Light is induced and emitted from the optical amplifier by the energy provided from the pump, and the light is reflected and amplified by the resonator into the optical amplifier so that a high density laser is emitted. However, the present invention is not limited thereto and may have various configurations.

In general, the type of laser is classified according to the medium of the optical amplifier, and the medium used is a gas medium, a liquid medium, a solid medium, a semiconductor medium and the like.

For example, a medium of a laser using a gas medium includes CO ₂ , He-Ne, Ar, Kr, CO, HF, H, N, and the like. In particular, the emitted light from the far-infrared spectrum of Ar and HF mixed gas or Kr and HF mixed gas is called excimer laser and was developed in 1975 by JJ Ewing and C. Brau. The wavelength of the ArF excimer laser is about 193 nm and the wavelength of the KrF excimer laser is about 248 nm.

In addition, a laser using a solid medium uses a single crystal or an amorphous material with a small amount of impurities, and examples thereof include an Nd-YAG laser and an Nd-YLF laser. The Nd-YAG laser has a wavelength of about 1.064 μm, and Nd, a rare earth material, is added to YAG (Yttrium Aluminum Garnet) used as a laser medium.

The laser used in the embodiment may be, but is not limited to, an Nd-YAG laser or an excimer laser, which is a laser in an ultraviolet (UV) region.

On the other hand, as shown in Figure 1a, when there is only one laser generating unit 110, the laser processing apparatus 100 according to the embodiment divides a single laser beam, a plurality of laser output units 121, 122 to be described later It may include an optical splitter 130 to supply to. The light splitter 130 may divide the laser generated by the laser generator 110, and the divided laser may be provided to each of the laser output units 121 and 122. Meanwhile, the optical splitter 130 may divide the laser generated by the laser generator 110 into any number, and is not limited as shown in FIG. 1B.

The support member 20 may support the wafer 10 and relatively move the plurality of laser output units 121 and 122 in the cutting direction.

The support member 20 may be moved in the X-axis direction or the Y-axis direction by a moving means such as a rail (not shown). However, the present invention is not limited thereto, and various methods and means may be used. That is, the support member 20 may relatively move the plurality of laser output units 121 and 122 by moving the wafer 10 in the X-axis direction or the Y-axis direction. Of course, the laser output units 121 and 122 may move to cut the wafer 10. In addition, when the support member 20 is moved, the moving direction of the support member 20 may proceed in parallel with the scribe line 11.

The laser output units 121 and 122 cut the wafer 10 by irradiating the wafer 10 with the laser generated by the laser generation unit 110.

That is, the plurality of laser output units 121 and 122 irradiates a laser on the entire surface of the wafer 10 and cuts the plurality of individual semiconductor chips to complete the cutting process. In this case, the wafer 10 is disposed on the predetermined support member 20 for the convenience of the cutting process.

The cutting of the wafer 10 is performed by the laser output from the laser output units 121 and 122, wherein the support member 20 or / and the laser output units 121 and 122 are in the X-axis direction or the Y-axis direction. It can be adjusted to be cut along the scribe line 11 of the wafer 10 by moving to.

The plurality of laser output units 121 and 122 may be disposed parallel to the cutting direction and spaced apart from each other. For example, the plurality of laser output units 121 and 122 may include a first laser output unit 121 and a second laser output unit 122, and the first laser output unit 121 and the second laser unit may be included. The output unit 122 may be spaced apart from each other by a predetermined distance, and the first laser output unit 121 and the second laser output unit 122 may be disposed parallel to the cutting direction of the wafer 10. In other words, when the cutting direction of the wafer 10 is in the X-axis direction, the plurality of laser output parts 121 and 122 may be disposed parallel to the X-axis direction. However, the number of the plurality of laser output units 121 and 122 is not limited thereto and may have various numbers depending on the working environment.

The separation distance d between the plurality of laser output units 121 and 122 may be such that the wafer 10 may be cooled. That is, the wafer 10 may be heated by the laser irradiated by the first laser output unit 121, and then naturally radiated during the time that the second laser output unit 122 moves by the separation distance d. . For example, the distance between the laser output units 121 and 122 may be 1 mm to 100 mm, but is not limited thereto.

The intensities of the first and second lasers L1, L2 may be different or the same. For example, the intensities of the lasers L1 and L2 output from the first laser output unit 121 and the second laser output unit 122 may have an intensity capable of cutting at least half of the thickness of the wafer 10. . That is, about half of the thickness of the wafer 10 is cut by the laser output from the first laser output unit 121, and the same place is irradiated with the laser output from the second laser output unit 122 to scan the wafer 10. Can be cut completely. However, the present invention is not limited thereto, and the intensity of the laser may be adjusted according to the number of the laser output units 121 and 122. On the other hand, the intensity of the laser as described above can be adjusted by the beam splitter 115 when there is one laser generating unit 110, each of the laser output unit (when there are a plurality of laser output (111, 112) Sizes of the lasers generated at 111 and 112 may be set to be different from each other, but are not limited thereto.

2 to 4, the cutting of the wafer 10 is performed by the laser output from the plurality of laser output units 121 and 122, and at this time, the support member 20 or / and the laser output unit ( The 120 may be adjusted to be cut along the scribe line 11 of the wafer 10 by moving in the X-axis direction or the Y-axis direction. Here, the scribe line 11 means a line in which the wafer 10 is cut.

In other words, first, the first laser output unit 121 and the second laser output unit 122 are aligned with the scribe line 11 of the wafer 10. Subsequently, a laser is output from the preceding first laser output unit 121 along the scribe line 11 of the wafer 10 to cut the wafer 10 by a predetermined depth (O), and thereafter, spaced apart by a predetermined distance. The laser is output from the second laser output unit 122 to completely cut the wafer 10.

That is, a plurality of lasers are irradiated along with the scribe line 11 of the wafer 10 with a time difference and an intensity difference, so that the intensity of the laser may be smaller than when cutting the wafer 10 with a single laser. When performing the cutting process of the wafer 10 using a laser having a large intensity, such as when cutting with a single laser, the peripheral area of the cut surface may be damaged by the laser of a large intensity, for example, insoluble, such as an eluate. Water may be produced or thermal damage may occur. On the other hand, when cutting the wafer 10 using a plurality of lasers as in the embodiment, since a laser of relatively small intensity can be used, damage to the wafer 10 as described above can be prevented. In addition, since the plurality of lasers are irradiated to the cutting points with a predetermined time difference, the wafer 10 may be intermediately cooled. Accordingly, the wafer 10 may be intermediately cooled to further reduce thermal damage of the wafer 10.

As shown in FIG. 2, an incision is made by a laser generated at the first laser output unit 121 to a predetermined depth, and then, when the wafer 10 is cooled to some extent, a laser generated at a second laser output unit 122 that follows. By completely cutting the wafer 10, thermal damage generated when the wafer 10 is cut can be reduced. In addition, if the damage caused by the heat of the wafer 10 is reduced, the yield and quality are improved when the wafer 10 is processed into a memory or an LED.

3 and 4 show an example of a process of cutting the wafer 10 using the laser processing apparatus 100 of the embodiment. The laser (O) irradiated from the first laser output unit 121 and the laser (O ') irradiated from the second laser output unit 122 are along the scribe line 11 of the wafer 10 in the X-axis direction or Y Proceeding in the axial direction, the wafer 10 can be cut as shown in FIG.

Referring to FIGS. 5A and 5B, according to the conventional laser processing apparatus of FIG. 5A, it is possible to confirm a place where thermal damage is wide around the scribe line 11 of the wafer 10, but the laser processing apparatus of the embodiment of FIG. 5B. According to this, it can be seen that the thermal damage around the scribe line 11 of the wafer 10 is significantly reduced compared to FIG. 5A.

6 is a schematic view showing a laser processing apparatus according to another embodiment. Hereinafter, a description of the same components as in the embodiment shown in FIG. 1 will be omitted.

Referring to FIG. 6, the laser processing apparatus 100 of the embodiment includes a laser generator 110 generating a laser, and a plurality of laser output units 121 and 122 that irradiate the workpiece with the generated laser to cut the workpiece. And supporting the workpiece, adjusting the laser intensities of the support member 20 and the plurality of laser generators 111 and 112 to relatively move the plurality of laser output units 121 and 122 in the cutting direction. It may include a control unit 140 for controlling the movement of the (20).

The laser processing apparatus 100 may further include an optical unit 150 that recognizes information such as a work environment of cutting the wafer 10 and provides the information to the controller 140. The optical unit 150 may be, for example, an analog camera or a CCD camera, but is not limited thereto.

The optical unit 150 shows information such as the working environment of cutting the wafer 10 to the supervisor, and transmits information such as the working environment to the controller 140.

Here, the plurality of laser output units 121 and 122 may be integrally formed. For example, as shown in FIG. 3, the plurality of laser output units 121 and 122 may be fixed by the connection member 160. However, the present invention is not limited thereto and may have various configurations.

When the plurality of laser output portions 121 and 122 are integrally formed, all the lasers are exactly vertically overlapped with the scribe lines 11 of the wafer 10 when cutting along the scribe lines 11 of the wafer 10. By irradiating, it is possible to prevent the scribe line 11 of the wafer 10 from being destroyed in a larger area than necessary. Thus, the yield of the wafer 10 can be improved.

The degree of cooling of the wafer 10 is adjusted by adjusting the separation distance of the plurality of laser output units 121 and 122 or by controlling the moving speed of the plurality of laser output units 121 and 122 and / or the supporting member 20. I can regulate it.

The controller 140 may include, for example, a central processing unit (CPU). However, the present invention is not limited thereto.

7 is a schematic view showing a laser processing apparatus according to another embodiment.

Referring to FIG. 7, the laser processing apparatus 100 of the embodiment may further include at least one gas injection unit between the plurality of laser output units 121 and 122 as compared with the embodiment of FIG. 6.

The gas injection unit 130 cools the wafer 10 by spraying a gas at a point where the laser irradiated from the laser output units 121 and 122 contacts the wafer 10.

For example, one gas injection unit 130 may be formed between the plurality of laser output units 121 and 122. However, the present invention is not limited thereto, and two or more may be formed.

The laser output units 121 and 122 may include a first laser output unit 121 and a second laser output unit 122, and the gas injection unit 130 may include the first laser output unit 121 and the second laser output unit 121. It may be disposed between the laser output unit 122. Therefore, a part of the wafer 10 is cut by the laser irradiated by the first laser output unit 121, the wafer 10 heated by the gas injection unit 130 is cooled, and the second laser output unit ( The laser irradiated by 122 may cut the wafer 10 again.

As such, since the gas injection unit 130 is formed between the laser output units 121 and 122, heat damage generated when the wafer 10 is cut by the laser may be prevented. In addition, when the damage caused by heat is reduced, the yield and quality are improved when the wafer 10 is processed into a memory or an LED.

In addition, the eluate is generated while the wafer 10 is dissolved by the heat of the laser, and the eluate can be effectively removed by the gas injection.

The gas injection unit 130 may include a nozzle 131 for injecting gas and a gas supply unit 132 communicating with the nozzle 131 to supply gas.

The nozzle 131 has a structure in which the cross-sectional area is gradually reduced, and may be a device for injecting a gas into a free space by converting the pressure energy of the gas flowing therein into the velocity energy of the gas. The size, shape, length, etc. of the nozzle 131 are not limited, and may be variously changed according to a process or a wafer.

In addition, the nozzle 131 may have a structure in which the injection angle and the injection distance are adjusted. For example, the nozzle 131 may be rotatably coupled to the pneumatic cylinder 135. At this time, the gas supply unit 132 and the nozzle 131 may be connected by the tube 133 for free movement of the nozzle 131. The tube may include, but is not limited to, a flexible material. The nozzle 131 may be controlled by the pneumatic cylinder 135 to the injection distance with the wafer 10, the injection angle by the rotation operation of the nozzle 131. However, the structure in which the injection angle and the injection distance of the nozzle 131 are adjusted is not limited thereto, and may have various structures.

Here, the injection angle refers to the degree to which the nozzle 131 is inclined with respect to the plane of the wafer 10, and the injection distance means that the laser irradiated from the laser output unit 120 to the wafer 10 at the exit of the nozzle 131. It means the shortest distance of the contact point (0).

The injection angle based on the wafer 10 surface of the nozzle 131 is not limited and may have a predetermined angle. For example, the injection angle may have an angle of 0 degrees to 90 degrees.

The distance (injection distance) between the nozzle 131 and the point where the laser is in contact with the wafer 10 is not limited, and is within the closest distance in the range that does not interfere with the pulse of the laser, or within the longest distance where the cooling effect is achieved. It may be the distance of. For example, the injection distance may be 10 mm to 50 mm.

The pressure of the gas supplied to the nozzle 131 is not limited, but may be 0.2 MPa (megapascal) to 0.4 MPa. When the pressure of the gas supplied to the nozzle 131 is less than 0.2 MPa, the velocity of the gas injected from the nozzle 131 also decreases, and thus does not have sufficient cooling effect, and the pressure of the gas supplied to the nozzle 131 is 0.4. This is because if larger than MPa, it may cause separation between the wafer 10 and the support member 20. Therefore, by adjusting the pressure of the gas supplied to the nozzle 131 to the above-mentioned degree, the wafer 10 can be cooled effectively, and separation between the wafer 10 and the support member 20 can be prevented.

The gas supply unit 132 includes all devices having a purpose of supplying gas, but may include a gas storage tank and a compressor. However, the present invention is not limited thereto.

The gas supply part 132 may be integrally formed with the nozzle 131, may be communicated by the pipe 133, or may be connected by another connection member. The valve 134 may be included between the gas supply part 132 and the nozzle 131.

As the gas is used for cooling, air or the like may also be used, and the type of gas used is not limited, and may include, for example, a gas or an inert gas having low reactivity. The gas may include, for example, nitrogen (N), neon (Ne), argon (Ar), and the like, and two or more gases may be mixed, but is not limited thereto.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is clearly understood that the same is by way of illustration and example only and is not to be taken by way of illustration, It can be seen that various modifications and applications are possible. For example, each component specifically shown in the embodiments can be modified and implemented. It is to be understood that all changes and modifications that come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.

Claims

A laser generating unit for generating a laser;
A plurality of laser output units for cutting the workpiece by irradiating the workpiece with the laser generated by the laser generator; And
A support member for supporting the workpiece and relatively moving the plurality of laser output units in a cutting direction;
The plurality of laser output unit is disposed in parallel to the cutting direction, the laser processing device is disposed spaced apart from each other.

The method of claim 1,
The laser generation unit includes a first laser generation unit and a second laser generation unit.

The method of claim 2,
And laser intensities generated by the first laser generator and the second laser generator are different from each other.

The method of claim 1,
And a beam splitter for dividing the laser generated by the laser generator into a plurality of beam splitters.

5. The method of claim 4,
The beam splitter,
And a laser processing apparatus for dividing the laser into a plurality of lasers having different intensities and supplying the laser to the laser output unit.

The method of claim 1,
The laser processing apparatus is formed integrally with the plurality of laser output unit.

The method of claim 1,
And a plurality of laser output units configured to be variable in position.

The method of claim 1,
At least one gas injection part for injecting gas into the workpiece; Laser processing apparatus further comprising a.

9. The method of claim 8,
The gas injection unit,
And a gas supply unit communicating with the nozzle and supplying gas to the nozzle.

9. The method of claim 8,
The gas is a laser processing apparatus comprising a gas or an inert gas weakly reactive.

9. The method of claim 8,
The gas, laser processing apparatus comprising at least one of nitrogen, neon, argon.

9. The method of claim 8,
And a controller configured to control the laser intensity of the plurality of laser generation units, the gas injection speed of the gas injection unit, and the movement of the support member.

The method of claim 12,
An optical unit that recognizes information such as a work environment of cutting a workpiece and provides the information to the controller; Laser processing apparatus further comprising.

The method of claim 1,
The workpiece is a laser processing apparatus comprising a semiconductor wafer.