CN111992903A - Method for synchronously peeling wafer by laser - Google Patents
Method for synchronously peeling wafer by laser Download PDFInfo
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- CN111992903A CN111992903A CN202010856050.5A CN202010856050A CN111992903A CN 111992903 A CN111992903 A CN 111992903A CN 202010856050 A CN202010856050 A CN 202010856050A CN 111992903 A CN111992903 A CN 111992903A
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- laser
- ingot
- wafer
- crystal ingot
- laser beam
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Classifications
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
- B23K26/00—Working by laser beam, e.g. welding, cutting or boring
- B23K26/36—Removing material
- B23K26/38—Removing material by boring or cutting
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
- B23K26/00—Working by laser beam, e.g. welding, cutting or boring
- B23K26/02—Positioning or observing the workpiece, e.g. with respect to the point of impact; Aligning, aiming or focusing the laser beam
- B23K26/06—Shaping the laser beam, e.g. by masks or multi-focusing
- B23K26/067—Dividing the beam into multiple beams, e.g. multifocusing
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
- B23K26/00—Working by laser beam, e.g. welding, cutting or boring
- B23K26/36—Removing material
- B23K26/40—Removing material taking account of the properties of the material involved
- B23K26/402—Removing material taking account of the properties of the material involved involving non-metallic material, e.g. isolators
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B28—WORKING CEMENT, CLAY, OR STONE
- B28D—WORKING STONE OR STONE-LIKE MATERIALS
- B28D5/00—Fine working of gems, jewels, crystals, e.g. of semiconductor material; apparatus or devices therefor
- B28D5/0005—Fine working of gems, jewels, crystals, e.g. of semiconductor material; apparatus or devices therefor by breaking, e.g. dicing
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- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Optics & Photonics (AREA)
- Mechanical Engineering (AREA)
- Plasma & Fusion (AREA)
- Processing Of Stones Or Stones Resemblance Materials (AREA)
- Mechanical Treatment Of Semiconductor (AREA)
Abstract
The invention discloses a method for synchronously stripping a wafer by laser, which comprises the following steps: (1) positioning and fixing the crystal ingot to be processed, and moving the laser beam to enable the focal plane of the laser beam to be positioned in the crystal ingot; (2) starting a laser, after laser beams are split by a spectroscope, one part of laser beams are incident from the front side of the crystal ingot to form front laser beams, and the other part of laser beams are reflected by a reflector and are incident from the back side of the crystal ingot to form rear laser beams; (3) controlling the front laser beam and the rear laser beam to process modified layers on the crystal ingot along respective focal planes; (4) after the modification layer is processed, corresponding reverse acting forces are applied to the upper surface and the lower surface of the crystal ingot, and two wafers with the same or different thicknesses are peeled. The whole machining process is simple to operate and easy to realize, machining time of the ingot modified layer is greatly saved, machining efficiency is high, different laser beam energies can be adopted according to different wafer stripping thicknesses, stripping of wafers with different thicknesses is achieved simultaneously, flexibility is high, and application range is wide.
Description
Technical Field
The invention belongs to the technical field of semiconductors, and particularly relates to a method for synchronously stripping a wafer by laser.
Background
Wafers are the material foundation in the field of semiconductor manufacturing, and ingot stripping technology is the key to obtaining high quality wafers. The conventional diamond wire cutting mode has the problems of low processing efficiency, large loss of processing tools and processed materials and the like, so that the requirement of large-size wafer production is difficult to meet. The wafer belongs to a hard and brittle material, and the laser stealth processing technology has great application potential in the aspect of ingot stripping.
The publication No. CN106216856B entitled "bifocal laser processing system and processing method thereof" discloses a bifocal laser processing system and processing method thereof, which divides a laser beam into two beams by a polarizing plate, respectively forms explosive dots inside the transverse and longitudinal cutting lines of an LED wafer, and realizes cutting of core particles. The LED chip is mainly used for separating the LED wafer along the mutually staggered cutting paths, the cut section is an irregular step surface, the generation of the step surface increases the light emitting area of the LED core particles, and the light emitting brightness of the LED core particles is improved.
The publication number "CN 102689092A," entitled "method and apparatus for precision machining of solar wafer using dual laser beams," discloses a method and apparatus for precision machining of solar wafer using dual laser beams, which uses dual laser beams to successively machine solar wafer, the energy of the laser beams is lower than and higher than that of the wafer, based on the nonlinear effect of the superposition of two beams of laser, the total energy of them is lower than that of a single beam of laser reaching the same effect, improves the use efficiency of laser energy, and reduces the machining cost.
Although the two methods disclose that the laser beam is divided into two beams, the functions of the two methods are different, and the two methods are not specially applied to the ingot peeling process, so that a method for efficiently and synchronously peeling the wafer from the ingot is sought, and the method has very important significance for improving the wafer processing efficiency and the yield.
Disclosure of Invention
In view of the above disadvantages, the present invention provides a method for synchronously peeling off a wafer by laser, which is easy to implement, and can simultaneously obtain two wafers with the same or different thicknesses by synchronously processing from two sides of an ingot in a light splitting manner, thereby greatly improving the processing efficiency.
A method for synchronously peeling a wafer by laser comprises the following steps:
(1) positioning and fixing the crystal ingot to be processed, and moving the laser beam to enable the focal plane of the laser beam to be positioned in the crystal ingot;
(2) starting a laser, after laser beams are split by a spectroscope, one part of laser beams are incident from the front side of the crystal ingot to form front laser beams, and the other part of laser beams are reflected by a reflector and are incident from the back side of the crystal ingot to form rear laser beams;
(3) controlling the front laser beam and the rear laser beam to process modified layers on the crystal ingot along respective focal planes;
(4) after the modification layer is processed, corresponding reverse acting forces are applied to the upper surface and the lower surface of the crystal ingot, and the wafers are respectively stripped from the upper surface and the lower surface of the crystal ingot.
In a preferred embodiment of the present invention, in the step (1), the ingot to be processed is positioned and fixed by a jig.
As a preferable mode of the present invention, the step (1) is performed by moving the laser beam in an axial direction of the ingot so that a focal plane of the laser beam is located inside the ingot.
As a preferable aspect of the present invention, the ingot is silicon, silicon carbide, sapphire, gallium nitride, or the like.
In a preferred embodiment of the present invention, in the step (4), the vacuum chuck is used to suck the upper and lower surfaces of the ingot, and simultaneously the ingot is pulled in a direction away from the ingot, so as to respectively strip the wafers from the upper and lower surfaces of the ingot.
As a preferable scheme of the invention, the pulse width of the laser beam is 200 fs-10 ns, the wavelength is 355 nm-1064 nm, the energy is 10 muJ-300 muJ, and the scanning speed is 50 mm/s-200 mm/s.
As a preferable scheme of the present invention, in the step (4), whether the modified layer is processed is monitored in real time by an online monitoring device, wherein the online monitoring device includes an acoustic emission module and a CCD system. The acoustic emission module is used for monitoring acoustic signals, and the CCD system is used for observing the condition of the modified layer and monitoring the forming state of the modified layer in the crystal ingot in real time.
In a preferred embodiment of the present invention, the thickness of the wafers peeled from the upper and lower surfaces of the ingot is the same or different, and the thickness of the wafers is 200 to 600 μm.
The invention has the beneficial effects that: the method for synchronously peeling the wafer by the laser reasonably adopts a laser beam splitting mode, acts on the crystal ingot from the front side and the back side of the crystal ingot respectively by adjusting the energy of the laser beam, synchronously forms the modified layer, and peels the wafer by the vacuum chuck.
The invention is further illustrated by the following structural drawings and examples.
Drawings
FIG. 1 is a schematic view of the process of the present invention.
Fig. 2 is a schematic view 1 of the structure of an ingot in the present invention as it is being processed.
FIG. 3 is a schematic view 2 of the structure of an ingot in the present invention as it is being processed.
Fig. 4 is a schematic view 3 of the structure of an ingot in the present invention as it is being processed.
Detailed Description
Example 1: in the method for synchronously peeling off the wafer by using the laser provided by the embodiment, referring to fig. 1 and 2, an ingot 9 to be processed is fixed by a clamp 10, and the ingot 9 in the embodiment is silicon carbide. The laser beams 7, 12 are moved axially along the ingot 9 so that the respective focal planes 8, 11 of the laser beams 7, 12 are located inside the ingot 9. And starting the laser 1, splitting the laser beam with the pulse width of 4ns, the wavelength of 1030nm and the energy of 100 mu J by the beam expander 2 and the beam splitter 3, wherein one part of the laser beam 12 enters from the front side of the crystal ingot 9 after passing through the condenser 13, the other part of the laser beam 7 enters from the back side of the crystal ingot 9 after passing through the reflector 4 and the condenser 6, and the energy is respectively set to be 50% and 50%. The laser beams 7, 12 are controlled to process the modified layers 15, 16 along the focal planes 8, 11 at scanning speeds of 100mm/s and 150mm/s, respectively. Referring to fig. 3, when laser beams 7 and 12 are applied to modified layers 15 and 16 in ingot 9 to penetrate in the radial direction, wafers 17 and 14 are peeled from ingot 9 by applying a pair of vacuum chucks 18 and 5 to the upper and lower surfaces of ingot 9, respectively, and pulling them in opposite directions, as shown in fig. 4.
Example 2: in the method for synchronously peeling the wafer by using the laser, the crystal ingot 9 to be processed is fixed by the clamp 10, and the crystal ingot 9 in the embodiment is silicon. Laser beams 7 and 12 are moved axially along ingot 9 so that the respective focal planes 8, 11 of laser beams 7, 12 are located inside ingot 9. The laser 1 is started, laser beams with the pulse width of 800fs, the wavelength of 1064nm and the energy of 80 muJ are split by the beam expander 2 and the beam splitter 3, wherein one part of the laser beams 12 are incident from the front side of the crystal ingot 9 after passing through the condenser 13, the other part of the laser beams 7 are incident from the back side of the crystal ingot 9 after passing through the reflector 4 and the condenser 6, and the energy is respectively set to be 30% and 70%. The laser beams 7 and 12 are controlled to process the modified layers 15 and 16 along the focal planes 8 and 11 at scanning speeds of 120mm/s and 170mm/s respectively. When the laser beams 7, 12 are applied to the modified layers 15, 16 in the ingot 9 and penetrate in the radial direction, a pair of vacuum chucks 18, 5 are respectively applied to the upper and lower surfaces of the ingot 9 and are pulled in the opposite directions, and wafers 17, 14 can be peeled from the ingot 9.
Example 3: in the method for synchronously peeling off the wafer by using the laser, the crystal ingot 9 to be processed is fixed by the clamp 10, and the crystal ingot 9 in the embodiment is sapphire. Laser beams 7 and 12 are moved axially along ingot 9 so that the respective focal planes 8, 11 of laser beams 7, 12 are located inside ingot 9. The laser 1 is started, laser beams with pulse width of 10ps, wavelength of 532nm and energy of 120 mu J are split by the beam expander 2 and the spectroscope 3, wherein one part of the laser beams 12 are incident from the front side of the crystal ingot 9 after passing through the condenser 13, the other part of the laser beams 7 are incident from the back side of the crystal ingot 9 after passing through the reflector 4 and the condenser 6, and the energy is respectively set to be 40% and 60%. The laser beams 7 and 12 are controlled to process the modified layers 15 and 16 along the focal planes 8 and 11 at scanning speeds of 80mm/s and 160mm/s, respectively. When the laser beams 7, 12 are applied to the modified layers 15, 16 in the ingot 9 and penetrate in the radial direction, a pair of vacuum chucks 18, 5 are respectively applied to the upper and lower surfaces of the ingot 9 and are pulled in the opposite directions, and wafers 17, 14 can be peeled from the ingot 9.
The above examples are only preferred embodiments of the present invention, and the present invention is not limited to all embodiments, and any technical solution using one of the above examples or equivalent changes made according to the above examples is within the scope of the present invention. The method for synchronously peeling the wafer by the laser reasonably adopts a laser beam splitting mode, acts on the crystal ingot from the front side and the back side of the crystal ingot respectively by adjusting the energy of the laser beam, synchronously forms the modified layer, and obtains the wafer by peeling through the vacuum chuck.
Variations and modifications to the above-described embodiments may occur to those skilled in the art, which fall within the scope and spirit of the above description. Therefore, the present invention is not limited to the specific embodiments disclosed and described above, and some modifications and variations of the present invention should fall within the scope of the claims of the present invention. Furthermore, although specific terms are employed herein, they are used in a generic and descriptive sense only and not for purposes of limitation. It is within the scope of the present invention to employ the same or similar methods as described in the above embodiments of the present invention.
Claims (10)
1. A method for synchronously peeling a wafer by laser is characterized by comprising the following steps:
(1) positioning and fixing the crystal ingot to be processed, and moving the laser beam to enable the focal plane of the laser beam to be positioned in the crystal ingot;
(2) starting a laser, after laser beams are split by a spectroscope, one part of laser beams are incident from the front side of the crystal ingot to form front laser beams, and the other part of laser beams are reflected by a reflector and are incident from the back side of the crystal ingot to form rear laser beams;
(3) controlling the front laser beam and the rear laser beam to process modified layers on the crystal ingot along respective focal planes;
(4) after the modification layer is processed, corresponding reverse acting forces are applied to the upper surface and the lower surface of the crystal ingot, and the wafers are respectively stripped from the upper surface and the lower surface of the crystal ingot.
2. The method for synchronously peeling off the wafer by laser as claimed in claim 1, wherein the ingot to be processed is positioned and fixed by a jig in the step (1).
3. The method for laser synchronous lift-off of a wafer as claimed in claim 1, wherein the step (1) is carried out by moving the laser beam in the axial direction of the ingot so that the focal plane of the laser beam is located inside the ingot.
4. The method of claim 1, wherein the ingot is silicon, silicon carbide, sapphire or gallium nitride.
5. The method for synchronously peeling off the wafer by the laser as claimed in claim 1, wherein in the step (4), the upper surface and the lower surface of the ingot are sucked by the vacuum chuck, and simultaneously, the wafer is peeled off from the upper surface and the lower surface of the ingot by pulling the vacuum chuck in a direction away from the ingot.
6. The method for synchronously peeling the wafer by the laser as claimed in claim 1, wherein the pulse width of the laser beam is 200 fs-10 ns, the wavelength is 355 nm-1064 nm, the energy is 10 muJ-300 muJ, and the scanning speed is 50 mm/s-200 mm/s.
7. The method for synchronously peeling off the wafer by laser as claimed in claim 1, wherein in the step (4), whether the modified layer is processed or not is monitored in real time by an online monitoring device, and the online monitoring device comprises an acoustic emission module and a CCD system.
8. The method for synchronously peeling the wafer by the laser as claimed in claim 1, wherein the thickness of the wafer is 200 μm to 600 μm.
9. The method of laser synchronized lift-off of a wafer as set forth in any one of claims 1 to 8, wherein the thickness of the wafer lifted off from the upper and lower surfaces of the ingot is different.
10. The method of laser synchronized lift-off of a wafer as claimed in any one of claims 1 to 8, wherein the thickness of the wafer lifted off from the upper and lower surfaces of the ingot is the same.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
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| CN202010856050.5A CN111992903A (en) | 2020-08-24 | 2020-08-24 | Method for synchronously peeling wafer by laser |
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| CN202010856050.5A CN111992903A (en) | 2020-08-24 | 2020-08-24 | Method for synchronously peeling wafer by laser |
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| CN111992903A true CN111992903A (en) | 2020-11-27 |
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113523551A (en) * | 2021-07-21 | 2021-10-22 | 袁霞 | Negative-pressure stable special ceramic substrate laser cutting device and cutting method thereof |
| CN113770555A (en) * | 2021-09-27 | 2021-12-10 | 北京大学 | Involute laser-assisted wafer cutting processing method and system and stress detection method |
| CN116765619A (en) * | 2021-11-24 | 2023-09-19 | 郭辉 | Water jet laser cutting system of conductive SiC crystal ingot |
| CN117020397A (en) * | 2023-09-20 | 2023-11-10 | 北京理工大学 | Silicon carbide ingot stripping method based on space-time synchronous focusing laser |
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| CN107030905A (en) * | 2016-01-07 | 2017-08-11 | 株式会社迪思科 | Chip generation method |
| CN108098147A (en) * | 2017-12-01 | 2018-06-01 | 广东工业大学 | A kind of double-sided laser processing method for PCB array micropores |
| CN108425082A (en) * | 2018-04-17 | 2018-08-21 | 沈阳航空航天大学 | A kind of Double-side Synchronous local laser heat treatment method improving aluminium alloy plate formability |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN1828863A (en) * | 2005-01-20 | 2006-09-06 | 株式会社迪斯科 | Wafer cutting method |
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113523551A (en) * | 2021-07-21 | 2021-10-22 | 袁霞 | Negative-pressure stable special ceramic substrate laser cutting device and cutting method thereof |
| CN113770555A (en) * | 2021-09-27 | 2021-12-10 | 北京大学 | Involute laser-assisted wafer cutting processing method and system and stress detection method |
| CN116765619A (en) * | 2021-11-24 | 2023-09-19 | 郭辉 | Water jet laser cutting system of conductive SiC crystal ingot |
| CN117020397A (en) * | 2023-09-20 | 2023-11-10 | 北京理工大学 | Silicon carbide ingot stripping method based on space-time synchronous focusing laser |
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Effective date of registration: 20211028 Address after: Building A1, innovation city, Songshanhu University, Dongguan, Guangdong 523000 Applicant after: Material Laboratory of Songshan Lake Applicant after: XI'AN INSTITUTE OF OPTICS AND PRECISION MECHANICS, CHINESE ACADEMY OF SCIENCES Address before: Building A1, innovation city, Songshanhu University, Dongguan, Guangdong 523000 Applicant before: Material Laboratory of Songshan Lake |
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Application publication date: 20201127 |